On September 1, 1932, President Luis Miguel Sánchez dispatched two regiments of the Peruvian Army to Leticia and Tarapacá; both settlements were in the Amazonas Department, now in southern Colombia.

The same day, thousands of Colombian students marched through the streets of Bogotá chanting, "Sánchez Cerro will die and Colombia will defy!"

Vásquez Cobo was declared the general of the Colombian Amazonian Navy, and 10 million dollars were approved by the Senate to fund his venture.

Sánchez believed that Colombia had no chance of defending itself since it lacked roads in the Amazon and a proper navy due to financial hardships brought on by the Thousand Days War.

It was not until December 1932 that General Alfredo Vásquez Cobo reached the mouth of the Amazon River with a fleet of old turn-of-the-century Colombian gun boats and new British destroyers that he acquired whilst in Europe.

At the end of December 1932, the flotilla of ships acquired by Colombia arrived in the Amazon, but President Enrique Olaya Herrera did not authorize the use of these to recover Leticia, hoping for a diplomatic solution instead.

Olaya insisted on an assault on Tarapacá in two communiqués of January 20 and 28, 1933 and named Vásquez Cobo Minister of War on commission to overcome difficulties and place it, with all authority, above the military in service.

On March 13, the Colombian forces, in order to break the Peruvian garrison of Puerto Arturo, mobilized the Pichincha gunboat with the Magdalena and Margarita armored launches under the command of General Efraín Rojas.

180 men from the Junambú battalion began to land, trying to occupy the surveillance post of Puerto Hilario on the Cotuhé River (near Buenos Aires between Cerro Tarapacá and Leticia).

On April 16, a Peruvian unit commanded by Lieutenant Colonel Oscar Sevilla fired rifles and machine guns at a Colombian infantry company from the Juanambú Battalion belonging to the Putumayo Detachment.

[15] In the early morning of May 7, 1933, the Colombian fleet made up of the Cordoba, Pichincha and Barranquilla gunboats moved through the Putumayo with two boats transporting 300 soldiers, the Peruvian garrison of Puca Urco under the command of Captain Raguz and Lieutenant Butron was composed by 52 soldiers and a single 75 mm cannon, they faced the Colombian forces that had seven 37 mm cannons and 12 machine guns.

The close confrontation did not allow the Colombian troops to land in the sector after being rejected, hours later Major Alfredo Collazos sent a radiogram to General Rojas: "In Saravia strong Peruvian resistance with artillery; three localized pieces and machine guns; in addition, a mine exploded near the right bank; fought for half an hour; lack of support from other ships prevented a longer combat time; place me a kilometer below, I ordered reconnaissance by boat."

Immediately afterwards, the Colombian flotilla landed the troops of the Amazonas Detachment at the base of the Cotton River without encountering resistance; Even so, four Peruvian soldiers who remained behind were captured, seizing military supplies and an aircraft workshop.

On May 26, Colombian troops made up of 10 Colombian soldiers under the command of Second Lieutenant Guillermo Aldana, who were still unaware of what had been agreed in Geneva the day before on the suspension of hostilities, surprised and captured four Peruvian officers, 77 Peruvian soldiers commanded by Captain Manuel Badárrago, taking several rifles and three machine guns from them.

On 30 April 1933, Peruvian President Sánchez Cerro was shot dead; 15 days later, his successor, Óscar Benavides, met with the head of the Colombian Liberal Party, Alfonso López Pumarejo, to secure an agreement to turn Leticia over to a League of Nations commission.