In 1941, the two countries went to war. As with all other such incidents, there are conflicting accounts to this day as to which side fired the first shot. Peru's version of events is that Ecuador had been making incursions into its territory since 1937 and occupied several border locations by 1940. Given these circumstances, the President of Peru,
Manuel Prado Ugarteche, ordered the formation of the
North Grouping, a military unit in charge of the
Northern Operational Theater, on January 11, 1941, consisting of two light divisions with three battalions each, plus four other independent battalions and three artillery batteries (one with six 105 mm guns) (
Delgado). In front of these forces, the Ecuadorian Border Security command had under its orders two Army battalions, the "Montecristi" and the "Cayambe", each one consisting of around 250 troops, armed with
7.92 mm Mauser rifles and a couple of
Czech 7,92 mm ZB-26 light machine-guns, plus two
Vickers-Maxim machine-guns. There was also a "Córdova" battalion, made up of around 100 troops, and a so-called "Mariscal Sucre" artillery battery, with 71 troops and no artillery pieces. In fact, the only artillery in the whole province of El Oro consisted of six
Italian 65 mm mountain guns, sold to Ecuador as leftovers from the Great War, and almost without shells. These guns were never put into action. (
Rodríguez, 1943). As for anti-aircraft defenses, the Ecuadorians had only a pair of
20 mm Breda guns deployed on Puerto Bolívar, which was the only port of entry for supplies, reinforcements, and weapons to arrive to the province, by sea, from the port-city of Guayaquil. The Ecuadorian Army of 1941 had not a single warplane. (
Rodríguez, 1943). It is claimed that on Saturday, July 5, 1941, the
Huaquillas unit of the Ecuadorian army invaded Peruvian territory, an action which originated a combat that extended across the entire
Zarumilla front, up to a region known as
Quebrada Seca. Ecuador's version of events is that Peru's invasion was an unprovoked act of aggression carried out with the explicit purpose of forcing Ecuador to sign an unfavorable treaty that would impose the status quo border line. A communiqué by Ecuador's Foreign Ministry indicated that Peruvian forces had been seen advancing north towards the border; all of the Peruvian troops stationed in
Tumbes had left
Zarumilla and those in
Piura and other nearby sites were in turn advancing towards
Zarumilla. According to the Ministry, the actions of the Ecuadorian army were limited to repelling the invasion which was occurring across much of the border. As support for its arguments, Ecuador has repeatedly cited the obvious difference in military might between the two countries, and the lack of preparedness of its forces. It has been speculated that Peru prepared to carry out an all-out invasion and could have been simply waiting for the slightest provocation. Ecuador has also cited Peru's history of conflict with its other neighbors as evidence of its belligerence. It has been pointed out, however, that these circumstances did not preclude Ecuador from attempting to lay claim to territories it still considered its own. Also, during the
War of the Pacific, the Ecuadorian military occupied a portion of the disputed territories. The much larger and better equipped Peruvian force of 13,000 men quickly overwhelmed the 1,800 Ecuadorian troops guarding the province of
El Oro. The Peruvian army had at its disposal a battalion of armor made up of
Czech LTP tanks, with artillery and air support. Beginning in the second third of the 20th century, Peru allegedly had one of the strongest military forces in South America, even as recently as 2005 it ranked second after Brazil and stronger than Argentina. The Ecuadorian president,
Carlos Arroyo del Río, kept Ecuador's best forces in
Quito, for fear of his political opponents (Arroyo would later resign on May 31, 1944, after much unrest in the country). Peru carried out the first use of
paratroops in combat in the
Western Hemisphere, dropping three paratroopers over the port-city of Puerto Bolívar (
Delgado), one of them having been rescued by Ecuadorian fishermen when he landed on the waters of the Jambelí channel. This attempt was largely successful in allowing a relatively easy takeover of El Oro towns, devoid by then of any Ecuadorian military presence after the short-lived ceasefire of July 26, brokered by the mediator countries (USA, Brazil and Argentina). After the ceasefire, most of the Ecuadorian troops, by now exhausted and without ammunition, left the field of battle and made their way out of El Oro, towards the city of
Cuenca. Thus, when Peru reopened the advance on July 29, which began with simultaneous bombings on the Ecuadorian towns of Machala, Puerto Bolívar, Pasaje, Santa Rosa, and Arenillas, plus a mission to the city of Guayaquil to drop leaflets, the Peruvian forces easily occupied the deserted towns of the province. A new ceasefire having been decreed to enter in effect on July 31 at 18:00 forced the Peruvian command to step up its efforts to occupy Machala and Puerto Bolívar, which they did with troops disembarked directly on Puerto Bolívar from the sea in the afternoon of July 31. (
Delgado) Even then, hostilities didn't cease, as Peruvian forces began operations against the Ecuadorian posts on the Amazonian jungle, most of which were easily overrun. With Peru occupying
El Oro and menacing
Guayaquil, plus pressure from the United States and Latin America to stop the hostilities as a sign of hemispheric unity against the
Axis powers (in World War II), Peru and Ecuador signed the
Rio de Janeiro Protocol.
Rio de Janeiro Protocol In May 1941, as tensions at the Ecuadorian–Peruvian border mounted and war was imminent, the governments of the United States of America, Brazil, and
Argentina offered their services in aiding in the mediation of the dispute. Their efforts failed to prevent the outbreak of hostilities on July 23, 1941, but the diplomatic intervention led to a definitive cease-fire being put into place on July 31. Despite this, limited
skirmishes continued to occur through the months of August and September in the Ecuadorian provinces of
El Oro and
Loja, as well as in the Amazonian lands. Ecuador accused Peru of continuing its advances into the highland province of
Azuay. On October 2, with military observers from the three mediating countries serving as witnesses, Ecuador and Peru signed the
Talara Accord, which created a demilitarized zone inside the provinces of El Oro and Loja, pending the signing of a definitive peace treaty. Diplomatic efforts continued, with the mediating countries being joined by
Chile. On January 29, 1942, on the final day of the third Pan-American Summit, held in
Rio de Janeiro, the foreign ministers of Ecuador and Peru,
Julio Tobar Donoso and
Alfredo Solf y Muro, signed a "Protocol of Peace, Friendship, and Boundaries", known as the
Rio de Janeiro Protocol. The observers from the United States, Brazil, Argentina, and Chile co-signed the document, becoming "Guarantors of the Protocol". The Rio Protocol was subsequently ratified by each country's congress on February 26, 1942. By the terms of the Protocol, Ecuador agreed to withdraw its long-standing claim for rights to direct land access to the
Marañón and
Amazon rivers; Peru agreed to withdraw Peruvian military forces from Ecuadorian territory. An area of of hitherto disputed territory in the Maynas region of the Amazonian basin was awarded to Peru, which had been established to be the
de facto possessor of the land since the end of the 19th century. The "status quo" line defined in the 1936 Lima Accord was used as the basis for the definitive border line; the previous border recognized current possessions, but not
sovereignty. Relative to the 1936 line, Ecuador ceded 18,552 km2 of previously possessed territory to Peru, while Peru ceded 5,072 km2 of previously possessed territory to Ecuador.
Ecuador's objections to the Protocol and thesis of Nullity Six times during the demarcation technical problems were found and referred to the Guarantors, with Brazil acting as lead. One of them, which involved the then contested
Cordillera del Cóndor, was submitted to arbitration by Captain Braz Dias de Aguiar. Both countries initially accepted the arbiter's award, issued July 1945, and demarcation began in the area according to that ruling. During 1943 and 1946 the
United States Air Force performed several aerial reconnaissance missions over the
Cordillera del Cóndor region (losing 2 aircraft and 14 men in accidents.) to help in the demarcation efforts. They found that the
Cenepa river was much longer than previously thought and that it runs between the
Zamora and the
Santiago. This finding conflicted with article VIII, point B-1 of the Rio Protocol, which laid out delineation of the border for that area as follows: :
From the Quebrada de San Francisco, the watershed between the Zamora and Santiago Rivers, to the confluence of the Santiago River with the Yaupi; The difficulty was that there is not one watershed between the Zamora and the Santiago, but two, as interpreted by Ecuador. This resulted in Ecuadorian president
Galo Plaza halting demarcation in 1949. About 78 kilometers of border were left unmarked. In 1953 Ecuador withdrew from the Demarcation Commissions, claiming the Protocol "impossible to implement" in that area. On September 29, 1960, Ecuadorian president
José María Velasco Ibarra declared the Rio Protocol null and void. (Peruvian analysts have speculated that this was a politically motivated move by Velasco Ibarra, who was considered a populist, but evidence to support this assertion is totally circumstantial). With the sole exception of
Cuba, the American community did not approve of Ecuador's diplomatic move, with the United States sending a letter of protest to Ecuador. The arguments for what is called Ecuador's
thesis of nullity varied, but they were generally the following: • It was imposed by military force. • It was signed while Ecuadorian towns were under occupation; invasion and occupation of nation states are prohibited by international law. • International law does not accept the conquest of territory by force or violence. Even considering de facto possession (1936 status quo border line) Peru took about 14,000 km2 of territory. • There was lack of compliance by Peru in denying Ecuador free navigation in Amazonian rivers as stipulated. • It was a blow to the economic development of a South American country, which is contrary to existing pacts of cooperation. Peru's counter-arguments included the following: • Ecuador cannot unilaterally invalidate a protocol • The core argument on implementability is a demarcation issue, not a justification to invalidate the entire protocol • Peru disputes the notion that the protocol was imposed by
premeditated military force • Even though the protocol was signed while Peruvian troops were still occupying El Oro for tactical reasons, the Ecuadorian congress ratified it long after Peruvian troops had left • Several Peruvian governments restricted the navigation clause in response to Ecuador's position on the treaty • On the issue of conquest of territory by force, Peru has pointed out that the disputed territories (Tumbes, Jaén and Maynas) were not under
de jure Ecuadorian administration, and that the province of El Oro was not annexed to Peru Ecuador argued its thesis extensively for 30 years, but did not find support in the international community. Peru's position, on the other hand, was that a dispute did not exist at all after 1941, a position which lasted until 1995, when it was recognized as a problematic diplomatic issue. Maps published in Ecuador since the 1960s up to the end of the 20th century officially had to exclude the unmarked 78 kilometers of border, that is, the Rio Protocol line was drawn as unresolved, and to include what Ecuador considered as its own by right, according to the Pedemonte-Mosquera protocol (1830) line, which puts the
Marañón (
Amazon) river as the border between Peru and Ecuador. Such controversial maps of Ecuador, known in Ecuador as "Tufiño's map", were referred in Peru as
"mapa recortado del Peru" (
cut-off map of Peru). ==Paquisha War (1981)==