BOGOTA (Reuters) – Colombia yesterday filed a  formal complaint against Venezuelan President Hugo Chavez with  the Organization of American States, accusing the leftist  leader of meddling in its domestic affairs.

Tensions are high between the Andean neighbours over a  Colombian plan to allow the United States more access to its  military bases. Chavez is a bitter foe of Washington, while  Colombia’s conservative President Alvaro Uribe is an ally.

The OAS complaint came after Chavez attacked Colombia as a  “narco-state,“ ordered investigations of Colombian companies in  Venezuela and urged his socialist party supporters to reach out  to left-leaning Colombians and politicians.

Colombia’s ambassador to the OAS, Luis Hoyos, denounced  what his government saw as an “interventionist plan” by Chavez,  a Cuba ally who promotes socialist revolution as the  counterweight to US influence in Latin America.

“This project violates the fundamental principles of  relations between states,” Hoyos said in an address to the OAS  session in Washington.

Chavez has clashed before with Uribe, who has received US aid to battle Marxist rebels and cocaine traffickers.

The Venezuelan president sees the base plan as US  “imperialist” aggression and has taken economic measures  against his neighbour, including ending a deal to supply cheap  fuel and threatening Colombian imports.

Chavez late on Tuesday warned he could cut off diplomatic  ties with Colombia over the bases proposal and is expected to  try to rally opposition to it at a South American leaders’  summit on Friday in Argentina.

Colombia, the world’s No. 3 coffee exporter and a major oil  producer, says the deal will allow the US military to use at  least seven bases for drug and counter-insurgency missions.

Although Bogota says US forces will not have offensive  capabilities at the bases, the announced plan has fuelled  concerns in the region.