Venezuelan President Hugo Chavez on Friday said that a "mercenary" arrested for entering the country illegally had "confessed" to having been a member of the US Marines - serving in Iraq and Afghanistan.

However, the president said the man had not been forthcoming with information about why he was in the country.

"He confessed to having been a Marine. He said he had served in the Marines, but he refuses to cooperate," Chavez said.

"He has all the appearances of a mercenary," he said, adding that a notebook had been seized from the man that contained written coordinates.

Chavez, who is running for re-election in October, has repeatedly raised the possibility of violent actions by what he claims are a US-backed opposition ahead of the elections.

"I'm struck by the fact that just a few weeks before the election, this has happened," he said. Opponents of Chavez say that he is keen to raise the prospect of external threats to enhance his domestic standing.

Washington said in a statement that it had not been formally notified by Venezuelan authorities.

"If it has in fact detained a US citizen, we are confident Venezuela will uphold its obligations under the Vienna Convention on Consular Relations and grant US consular officials access to any detained US citizen without delay," said the US State Department.

Chavez, who has held power since 1999, has been involved in a succession of diplomatic disputes with the US and the two countries have not had ambassadors in each other's capitals since 2010.

rc/slk (AFP, Reuters)