Ministers from the 12-nation group began talks late Thursday amid Venezuelan warnings a war was imminent and as Colombia prepares for transition from outgoing President Alvaro Uribe to President-elect Juan Manuel Santos.
The Union of South American Nations was founded after a May 2008 treaty and brings together Argentina, Bolivia. Brazil, Chile, Colombia, Ecuador, Guyana, Paraguay, Peru, Suriname, Uruguay and Venezuela.
Unasur called the emergency meeting after Venezuela broke off diplomatic relations with Colombia last week. Showing photographs and other documents, Bogota accused Caracas of aiding Colombian rebel group FARC, a charge Venezuela denied and followed up by breaking off diplomatic relations.
An angry war of words between Uribe and Venezuelan President Hugo Chavez raised concerns that the tension could lead to armed conflict. Last year, Chavez amassed 15,000 troops on the Colombian border after the signing of a Colombia-U.S. military pact that Caracas alleged was in preparation for an invasion.
U.S. anti-narcotics forces are sharing the use of Colombian military bases in a long-running battle against drug warlords behind a cocaine trail to North America. Colombia says FARC rebels are bankrolled by the drug gangs and in turn aid the narcotics smuggling operations.
Tensions between Colombia and Venezuela flared up when Uribe accused Chavez of harboring FARC. Santos, being sworn in as president Aug. 7, says he is ready to try a less confrontational approach with Chavez.
Critics of Chavez say Venezuela's escalation with Colombia is linked to the Sept. 26 National Assembly election and is aimed at deflecting attention from the deepening recession. Venezuela was the only major Latin American country to record a negative growth in 2009, and further shrinking of the economy continued in the first half of 2010.
Despite poor economic performance, Venezuela invested heavily into building up its military forces. Caracas also borrowed from Moscow to buy additional hardware.
Chavez faces challenge from numerous "independent" candidates arrayed against his government in an opposition alliance.
Analysts said Chavez aides hoped the tension with Colombia would help galvanize the Venezuelan people behind the ruling United Socialist Party before the election.
Last week Chavez raised temperatures when he accused Colombia of planning to invade Venezuela. He then threatened to halt crude oil exports to the United States in retaliation for its support of Colombia.
Venezuela is the fifth-largest source of oil imported by the United States and supplies about a million barrels a day.