By Andrew Cawthorne
CARACAS (Reuters) - An American arrested in Venezuela while entering illegally from Colombia is a former U.S. Marine and is refusing to explain himself under interrogation, President Hugo Chavez said on Friday.
The United States is expressing skepticism over the latest incident between the two ideologically opposed nations, but says its diplomats should be given access to the man if Chavez's statements are true.
The socialist Chavez is running for re-election at an October 7 vote and has been frequently invoking the possibility of violent actions by Venezuela's opposition with U.S. blessing.
"I'm struck by the fact that just a few weeks before the election, this has happened," he said, giving the latest details about the unnamed man in Venezuelan custody.
Opponents say Chavez, like Cuba's Castro brothers, likes to play up the idea of an external threat to bolster his own standing at home. His predictions of violence are, they say, particularly cynical given his own history of a failed military coup against then-President Carlos Andres Perez in 1992.
Venezuela says the American, of Hispanic origin, was arrested earlier this month crossing into Venezuela from Colombia with a notebook full of geographic coordinates that he tried to destroy.
Having originally said the man appeared to be a mercenary, Chavez added on Friday that he was largely resisting questioning by security forces though he had acknowledged being a Marine.
"He has military background, he confessed to being a Marine ... to having served in the Marines," Chavez said in brief remarks to journalists, adding that nothing had been proved against the man yet.
"He refused to give information."
An official at the U.S. Embassy said it still had no official information about the supposed arrest.
"We have not been notified by the government of Venezuela about the arrest of this alleged U.S. citizen," said the official, who was not authorized to give his name.
"If in fact Venezuela has detained a U.S. citizen, we are confident that Venezuela will uphold its obligations under the Vienna convention on consular relations and grant U.S. consular office access to any detained U.S. citizen without delay."
According to Chavez, the arrested man's passport shows he has traveled extensively in the Middle East and Asia - Iraq in 2006, Afghanistan various times around 2004, and Jordan in 2007.
"We are not making anything up," he said in response to Washington's doubts.
Chavez is the United States' principal irritant in the region, and U.S. President Barack Obama's government would undoubtedly be pleased should he lose the election in October.
Chavez, though, is looking like a winner.
Back on the campaign trail after two bouts with cancer in a year, the president is leading his opponent, former state governor Henrique Capriles, by double digits in most polls.
Chavez's nearly 14-year-rule of South America's top oil exporter has been punctuated by diplomatic spats with the United States. His fierce "anti-imperialist" rhetoric has played well with his power-base among Venezuela's poor majority, and made him one of the world's most controversial leaders.
(Editing by David Brunnstrom)