Caracas  - Relations between Venezuela and Colombia have gone ice cold once again.

Venezuelan President Hugo Chavez has frozen relations with Bogota, recalled the ambassador to Caracas last week and accused Colombian President Alvaro Uribe of aggression. The diplomatic row has been followed by dueling accusations.

The latest tensions come amid a planned defence treaty between the United States and Colombia. Chavez, a left-wing populist who regularly skewers Washington, has expressed concern, but other government leaders in the region are raising their own questions.

Meanwhile, Colombia has renewed its long-standing claims that Venezuela is arming FARC. The rebels were found to have Swedish-made rocket launchers that were acquired by Venezuela in the 1980s, according to Colombian intelligence sources cited in The New York Times.

Bogota is considering boosting US access to military bases in Colombia. The United States wants to use seven Colombian bases, Defence Minister Freddy Padilla said this week.

The official reason for allowing additional access is the fight against drug trafficking, which fuels the Revolutionary Armed Forces of Colombia (FARC), Marxist rebel group that has waged civil war for more than 40 years.

Calling the narcotics interdiction a pretense, Chavez has accused the US of seeking to establish Colombia as a "Yankee" platform for attacks on other countries in Latin America.

The uproar has again undermined relations Caracas and Washington, after a brief thaw that followed the inauguration of President Barack Obama in January.

Chavez is trying to put the US-Colombian military plans on the agenda of a meeting next week in Quito of South American countries, and he may receive support from other leaders in the region.

Chavez told international journalists gathered Wednesday in Caracas that the proposed US use of Colombian bases "could be the first step toward war" in the region, calling the United States the "most aggressive country in the world." He said he was "frustrated" that Obama had decided to send "more planes, more dollars, more helicopters and more bombs"

Colombian allegations of Venezuelan collusion with FARC are an attempt by Uribe to distract from the US basing controversy, Chavez charged.

Uribe, touring South American capitals to ease concerns about Colombia's defence pact with Washington, spent Wednesday in Brazil.

Chilean President Michelle Bachelet and Brazilian Foreign Minister Celso Amorim have both asked for clarification about the military treaty. Amorim was expected to press the issue in a scheduled meeting with Obama national security adviser James Jones this week in Brasilia.

Amorim, meanwhile, has quietly cast doubts on Colombia's allegations that Caracas is aiding FARC.

It is not clear whether the '80s-era weapons fell into the hands of FARC fighters before or after Chavez first took office in 1999. Amorim, further, has wondered aloud whether the weapons might have been stolen.

Chavez himself has been equivocal on the issue.

"I am not an ally of the FARC," he said. "I don't help it, but I am also not its enemy." (dpa)