With the opening of the Summer Games now just 91 days away, the first day of an Olympic media summit staged by the United States Olympic Committee (USOC) was dominated by a single topic -- security.

From the opening news conference to the last, U.S. athletes and officials taking part in four-days of briefings are prepared to be grilled about their thoughts regarding security, which have been heightened by recent bombings in Athens.

"It (security) is the issue of these games," USOC chief executive Jim Scherr said. "And I don't think the questions will stop from now until the last athlete has left the Games and gone home."

Athens organisers will spend over a $1 billion on security, employ over 70,000 police, military and law enforcement personnel to put in place a plan backed by NATO and the intelligence community of several countries, including the U.S.

The USOC also confirmed on Friday it would take 100 federal agents to Athens, who will liaise with Greek authorities to help protect the 550 American athletes and a support staff of 300.

"The bar's been raised a bit for these games," USOC security chief Larry Buendorf admitted.

"It was raised for Salt Lake City and it's even higher now."

"We will have 100-plus federal agents who will work in liaison with Greek authorities but this just allows better communication to help ensure safety."

SECURE AREA

Despite the fact U.S. popularity is dropping and the threat of terrorism increasing, the USOC was at pains to stress it has had no discussions about pulling out of the Games, which run from August 13-30.

USOC officials, however, conceded some athletes had voiced concerns but added none had pulled out, satisfied with the security measures that have been put in place.

"We're not going to put our athletes in harms way," U.S. chef de mission Herman Frazier said. "We believe that the things in place right now will give us a secure area to compete."

"Our athletes will go through a final briefing in June. Right now our plan is to let our athletes do whatever they need to do and go freely throughout Athens."

Contrary to earlier reports, the USOC said it had not advised athletes against wearing team uniforms when in public and had not placed any restrictions on where they could go in Athens when not competing.

However, officials have warned athletes to take a low key, respectful approach both while competing and out in public.

"There's nothing on the screen right now that would make us restrict our athletes from enjoying the Games," Buendorf said.

"There are plans in place to take care of what ever type of situation occurs and there is nothing right now we would do to restrict these athletes."

"There's nothing our there right now that would indicate that we need to do that."