Colombia has filed a formal complaint against Venezeula's president with the Organisation of American States (OAS), accusing him of interfering in Colombian affairs.

Bogota lodged the complaint against Hugo Chavez with the regional bloc on Wednesday, after the Venezuelan leader threatened to break ties with Colombia over its decision to allow more US troops on its soil.

Luis Hoyos, Colombia's ambassador to the OAS, told a meeting of the group in Washington that Chavez was running an an "interventionist plan" against the Colombian government.

"This project violates the fundamental principles of relations between states," Hoyos said.

Chavez said on Tuesday that he is set to sever relations with Colombia after it granted the US military increased access to military bases in the country.

"We have to prepare the rupture of relations with Colombia ... this is going to happen," Chavez told Nicolas Maduro, his foreign minister, in a conversation broadcast on state television on Tuesday.

Bogota has said the deal with Washington, which would allow the US military to increase its presence at seven bases under a 10-year lease agreement, is necessary to tackle drug trafficking.

'Declaration of war'

The US deployment on Colombian soil would be capped at 800 troops, according to the agreement, but Chavez has warned that the bases could be used as a launching point to unseat Latin American leaders.

"Those seven Yankee bases there are a declaration of war against the Bolivarian revolution and that's how we see it. A declaration of war," Chavez said.

Bogota and Caracas share a $7bn-a-year trade realtionship, but in light of the military deal, Chavez has threatened to shift many of the country's purchases to Argentina.

He also withdrew his ambassador to Bogota earlier this month, before sending him back several days later.

Venezuela's threat to cut ties with Colombia came before a regional summit in Bariloche, Argentina, on Friday, where Latin American leaders will discuss the US-Colombian security arrangement.

Bolivia and Ecuador, allies of Venezuela, have also criticised the troop deal, but a number of nations in the region have dismissed the concerns, saying that it is purely an internal matter for Colombia.