Venezuela insists it is fighting - not fuelling - the drugs trade
Corruption in Venezuela's government and military is allowing drug trafficking into the US to flourish, a US congressional report has said.
Venezuela provides "a safe haven" for Colombian armed groups operating along its border, the report says.
Venezuelan President Hugo Chavez has dismissed the report's findings, labelling it "a new lie" from the US.
The US says the annual flow of Colombian cocaine through Venezuela quadrupled between 2004 and 2007.
The report, by the Government Accountability Office, which is an arm of Congress, says corruption in Venezuela has extended a "lifeline" to Colombian rebels who profit through the drugs trade using sanctuaries along the border.
The report says that the situation risked reversing gains made in stemming the flow of drugs from Colombia.
"If illegal armed groups continue to find safe haven in Venezuela and receive support from Venezuela, the permissive atmosphere and lack of co-operation will likely adversely affect the security gains made in Colombia since 2000," the report said.
According to researchers who prepared the report, visiting both Venezuela and Colombia earlier this year, Venezuelan officials were bribed to facilitate Colombian cocaine shipments.
Mr Chavez, speaking on Friday after a copy of the report was leaked, said the US was "the top drug trafficking country on the entire planet".
Co-operation between Venezuelan and American drug enforcement agencies has declined sharply since 2005, when Mr Chavez accused US officials of spying, a charge they denied.