Brazilian President Luiz Inacio Lula da Silva and his Colombian counterpart, Alvaro Uribe, have held talks that included the diplomatic dispute between Colombia and Venezuela.
The two presidents met in a Colombian town to discuss the rift over Colombia's capture of a FARC rebel leader in Caracas last month.
Brazil and Mexico have offered to mediate the rift, which began after Colombia acknowledged paying bounty hunters to capture Rodrigo Granda.
Venezuelan President Hugo Chavez says Colombia violated his country's sovereignty. Last week, Venezuela froze trade relations with Colombia and recalled its ambassador from Bogota.
The Colombians say they plan to send Caracas proof that Colombian guerrillas are in Venezuelan territory.
Colombia is mired in a long-running civil war involving leftist rebels, rightist paramilitaries and the government. The conflict leaves thousands dead each year.