Agents of the U.S. Transportation Security Administration will be stationed at British airports during the Summer Olympic Games, British media reported Tuesday — the latest indication that authorities are scrambling to shore up security before the games open in 11 days.

M. Alex Johnson is a breaking news and projects reporter for NBCNews.com. Follow him on Twitter and Facebook.

Sky News, citing security sources, reported that the agents would begin arriving at Heathrow and other major UK airports next week.

Olympic organizers have come under withering criticism after G4S, the private contractor coordinating security preparations, said last week that it might not be able to supply enough guards. In response, the British military was asked to provide 3,500 extra personnel last week, government sources told NBC News.

"I knew it was going to happen," Sarah Hubble, a former G4S employee, told NBC News. "When I was there, they were struggling and didn't have enough staff."

Errol Southers, who withdrew from consideration to be President Barack Obama's first TSA director in 2010 in a political struggle over unionization of TSA workers, said the Olympics would likely draw would-be terrorists like flies to honey.

"I think that, given the world stage as it is, it certainly sets an environment that is perfect," Southers said in an interview with NBC Los Angeles.

"We have what we call adaptive adversaries," said Southers, assistant chief of homeland security for the Los Angeles airport police. "They'll be looking for patterns, for routines — vulnerabilities and gaps in the security system."

Noting the "extraordinary number of VIPs" who will be at the games, Southers said, "It is a perfect stage for a terror attack if that's your agenda."

Sky News reported that TSA agents were drafted primarily to assist U.S. carriers, but it said the agents would also be working with British airlines.

The agents will not be allowed beyond boarding gates or onto British aircraft, it said.

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