April Revolution about the U.S. invasion. On April 24, 1965, three junior officers requested a meeting with President Donald Reid Cabral, who rejected the offer after he had received news of a suspected anti-government plot. When Chief of Staff Riviera Cuesta was instead sent to discuss with the officers at the August 16 military camp, he was immediately detained. A group of military constitutionalists and
Dominican Revolutionary Party (DRP) supporters then seized the Radio Santo Domingo building and issued calls of sedition while Constitutionalist officers distributed weapons and
Molotov cocktails to their civilian comrades. The transmissions prompted the garrison of the February 27 camp and a unit of the Dominican Navy's frogmen to defect. Large numbers of police officers abandoned their positions and changed into civilian clothing. On April 29, the
U.S. Ambassador to the Dominican Republic,
William Tapley Bennett, who had sent numerous reports to U.S. President
Lyndon Johnson, reported that the situation had reached life-threatening proportions for US citizens and that the rebels were communists. Bennett stressed that the U.S. had to act immediately, as the creation of an international coalition would be time-consuming. Contrary to the suggestions of his advisers, Johnson authorized the transformation of evacuation operations into a large-scale military invasion through Operation Power Pack, which was aimed to prevent the development of what he saw as a second
Cuban Revolution. It was the first overt U.S. military intervention in Latin America in more than 30 years, although it came on the heels of U.S.-backed coups in
Guatemala and
Brazil, as well as ongoing covert operations in
Cuba. At 2:16 a.m. on April 30, 1965, the 3rd Brigade of the
82nd Airborne Division landed at the
San Isidro Air Base and started the U.S. military intervention in the conflict. During the next couple of hours, two brigade combat teams and heavy equipment were also dispatched. At sunrise the 1st Battalion,
508th Infantry Regiment moved up the San Isidoro highway under the cover of Marine
F-4 Phantom jets flying from
Puerto Rico, securing a position east of the Duarte bridge. More units of the 82nd Airborne landed and secured the entire east bank of the Ozama River. Rebel positions across the river were destroyed by 105 mm howitzers. U.S. soldiers crossed the bridge and occupied a six-block area on the western side of the Duarte Bridge, but suffered casualties from sniper fire. The 1st Battalion
505th Infantry Regiment remained at the airbase and sent out patrols to the perimeter. A force of 1,700 Marines of the 6th Marine Expeditionary Unit occupied an area containing a number of foreign embassies. The locale was proclaimed an International Security Zone by the
Organization of American States (OAS). Earlier in the day, the OAS also issued a resolution calling the combatants to end all hostilities. At 4:30 p.m., representatives of the loyalists, the rebels, and the U.S. military signed a ceasefire that was to take effect at 11:45 p.m. That timing favored the
demoralized Loyalists, who had lost control of
Ciudad Colonial. On May 5, the OAS Peace Committee arrived in Santo Domingo, and a second definite ceasefire agreement was signed, which ended the main phase of the civil war. On May 6, Dominican rebels killed four Marines and captured two others, who were later released. Under the Act of Santo Domingo, the OAS was tasked with overseeing the implementation of the peace deal as well as distributing food and medication through the capital. The treaties failed to prevent some violations such as small-scale firefights and sniper fire. A day later, OAS members established the
Inter-American Peace Force (IAPF) with the goal of serving as a peacekeeping formation in the Dominican Republic. The IAPF had 1,748 Brazilian,
Paraguayan,
Nicaraguan,
Costa Rican,
Salvadoran and
Honduran troops and was headed by Brazilian General Hugo Panasco Alvim, with US Army General
Bruce Palmer serving as his deputy commander. General Palmer proposed sending U.S. troops to eliminate the northern rebel sector and shut down the rebel-held radio station, but Washington blocked any offensive operations involving U.S. troops. Utilizing Radio Santo Domingo as their primary weapon, the rebels launched a psychological campaign against the United States, the OAS, and the Loyalists. Through numerous outlets, studios, and transmission sites nationwide, they employed Radio Santo Domingo to incite a nationwide rebellion. In response, American forces initiated jamming operations, deploying
Army Security Agency (ASA) units on land, air force units in the skies, and naval ships at sea. Additionally, a reinforced company from the army's
7th Special Forces Group, led by Col. Edward Mayer, attacked critical relay sites beyond the capital. Their initial efforts were not effective, however, and rebel broadcasts continued to make their influence felt countrywide. On May 7, 1965, the Government of National Reconstruction (GNR) was established with Antonio Imbert Barrera as president. On May 13, the GNR launched an air attack on Radio Santo Domingo and its main transmitter sites. One of the planes accidentally strafed U.S. troops, prompting the Americans to return fire and shoot down another P-51 of World War II vintage. The following day, the GNR initiated an offensive against the rebel-held northern sector. They overwhelmed the rebels' initial defense line, seizing control of the majority of the city's industrial sector. By May 21, GNR troops had completed the destruction of the rebel northern zone and captured Radio Santo Domingo, and following talks with Constitutionalist leaders and
McGeorge Bundy, a ceasefire was in effect by May 25. ==United States withdrawal==