Washington warned Venezuela on Tuesday that it would suspend Venezuelan flights to the United States if Caracas carries out a threat to restrict US carriers flying to Venezuela in a simmering dispute over aviation rights.

Venezuela's civil aviation authority, INAC, announced in February it would restrict or suspend access for US airlines unless the Federal Aviation Administration lifts decade-old limits put on Venezuelan airlines by a March 30 deadline.

The airline spat is testing already strained ties between Washington and left-wing President Hugo Chavez, who has clashed with American officials over his alliance with Cuba and his fierce opposition to US free-market proposals in South America.

"Hopefully that will not happen. If that happens, it is not only possible or probable, but absolutely certain the US government... would suspend flights by Venezuelan airlines," US Ambassador to Caracas William Brownfield told reporters.

The FAA has proposed talks on April 17 with Venezuelan officials to resolve the dispute, the envoy said. It was unclear what specific measures US authorities would take to restrict Venezuelan flights to US airports.

Soon after Brownfield's statement, Venezuela reasserted it was now in compliance with international aviation standards and said Caracas would defend its ruling against US airlines.

"As a sovereign country, we can take the decision about who can and who cannot fly here," Infrastructure Minister Ramon Carrizalez said in a statement.

The Venezuelan restrictions would trim flights by American Airlines and completely halt operations by Continental Airlines and Delta Air Lines, should they take effect.

Caracas has struggled for about a decade to get the FAA to revise its 1995 ruling that the South American country had failed to fully comply with International Civil Aviation Organization safety standards.

Venezuela currently has an FAA category 2 rating, under which airlines are restricted from expanding US flight services and some are required to lease aircraft from a category 1 country to fly to US airports.

Venezuela briefly cancelled direct flights by US carriers in 1996 after Washington threatened to put a full ban on Venezuelan carriers flying to the United States.

Relations between the United States and oil supplier Venezuela are at one of their lowest points since Chavez came to power seven years ago promising to introduce sweeping social reforms for the poor majority.

A former soldier, Chavez accuses Washington of organizing a 2002 coup he survived and working to oust or kill him. The US government portrays the Venezuelan president as a growing threat to regional stability.