By Avril Ormsby
LONDON (Reuters) - The United States on Tuesday denied a newspaper report it was unhappy with British security arrangements for next summer's Olympics and said talk of a diplomatic row was "simply untrue."
The Guardian newspaper also said the United States was planning to send up to 1,000 of its agents, including 500 from the FBI, to protect American athletes and diplomats.
"The United States embassy has the utmost confidence in the British government's arrangements to ensure safety and security for the Olympic Games," the U.S. embassy in London said in a letter sent to the editor of the left-leaning newspaper.
"The United States has established an excellent collaborative relationship with the Metropolitan police."
The letter was read out by London Olympic organizing committee (LOCOG) Chief Executive Paul Deighton to a parliamentary committee looking at preparations for the Games.
He said the newspaper's report had "absolutely no basis of any experience I have had."
The United States, he said, has "a big team, they have got serious security concerns, so they'll want to work with us to make sure it's effective. As I say, they have said they are very happy with what we are doing."
The report came nearly two weeks after a source told Reuters more than 6,000 off-duty British troops, wearing civilian security uniform, looked set to be used at Olympic venues to help meet an expected shortfall in the number of civilian guards.
Britain was ready to use missiles to protect the Games from airborne attack, Defense Secretary Philip Hammond told parliament on Monday.
The interior ministry was currently deciding on the exact number and "mix" of guards needed to cover 10 million person-hours of guarding the Games, Deighton said.
He compared the troops' presence to that of those deployed at the Wimbledon tennis tournament who add "a very positive" experience and give spectators confidence.
"So from a qualitative point of view, of course, it would be attractive to have a military component and we see it as a mix to deliver what is by a long way the biggest event that this country has ever seen," he said.
Britain remains on high alert of attack despite its international threat level being lowered in July from severe to substantial, the third-highest level, meaning an attack is a strong possibility and might well occur without further warning.
Organizers are also wary of a potential threat from dissident Irish nationalists.
LOCOG chairman Seb Coe said talks were in an advanced stage for the Olympic torch to travel south from Northern Ireland to Dublin in the Republic to highlight the peace process.
Currently, it is not on the 8,000-mile route ahead of the 2012 Games, and it would be the only detour outside of the UK.
"From a personal perspective I would like to see just a small visit south of the border," Coe said.
(Reporting by Avril Ormsby; Editing by Jon Hemming)