DENVER - THREE men were charged with gun and drugs offenses on Tuesday but US authorities dismissed reports that they had serious plans to shoot Democratic presidential candidate Barack Obama and said they had posed no 'true threat.'

US Attorney Troy Eid said threatening comments attributed to the suspects in media accounts after their arrest in Aurora east of Denver on Sunday amounted to 'the racist ramblings of three meth heads.' The three men are all white. If elected, Mr Obama will be the first black US president.

'There is no credible threat,' Mr Eid told a news conference called after an initial investigation into the arrests, made on the eve of the Democratic Party convention in Denver where Mr Obama will be formally nominated for the Nov 4 election.

'There was insufficient evidence that the statements (of the suspects) constituted a true threat,' Mr Eid said.

Police in Aurora seized two rifles with hunting scopes, ammunition, body armour and a mobile methamphetamine lab from a rented pickup truck driven by one of the men during a traffic stop early on Sunday morning, court documents said.

The arrest of the driver, Tharin Gartrell, 28, led authorities to the two other men.

One of them, Nathan Johnson, 32, told federal agents that the third, Shawn Adolf, 33, had spoken of wanting 'to kill Obama on the day of his inauguration', according to an affidavit filed with the criminal complaints.

According to Johnson, the affidavit said, Adolf had said he would use a sniper rifle, like one found in the truck, to shoot Mr Obama from 'high ground.'

Mr Obama is scheduled to accept the nomination in a speech at an open-air football stadium, Invesco Field, in Denver. The inauguration of the next US president will take place in January of next year in Washington, DC.

The affidavit said Johnson, in whose name the truck was rented, also stated that he believed Gartrell was in the Denver area to help Adolf attack Obama, though he said he never specifically heard Gartrell threaten the Illinois senator.

Mr Eid said that investigators had yet to tie any of the weapons recovered in the investigation to any specific plot to attack the candidate.

Adolf and Johnson were both charged with illegal possession of a firearm and possession of methamphetamine. Johnson also was charged with illegal possession of body armor. Gartrell, a cousin of Adolf, faced a lesser drug charge.

Eid said he did not know if Obama had been informed of the case, but the prosecutor said he had briefed US Attorney General Michael Mukasey on the situation. -- REUTERS