LONDON: Britain's stretched border service is letting terror suspects slip into the country, a newspaper reported Sunday, quoting two unnamed Border Agency officials as saying several suspects had been waved through controls at London's Heathrow Airport since the beginning of the month.

The Observer newspaper's report - which Britain's Home Office declined to comment on - is the latest in a series of last-minute concerns to surface as London gets ready to host the 2012 Olympic Games. Officials are already under pressure over the failure of security contractor G4S to deliver some 10,400 personnel to protect stadiums and other events. The blunder has forced the government to call in an extra 3,500 troops to guard the games - that's over and above the 7,500 troops already promised to help out at some 100 venues and sensitive sites.

Blame has started to fly, with the Observer saying immigration staff had missed several members of a security watch list whose arrival in the country was meant to have been reported to counter-terrorism police or Britain's domestic intelligence service.

The newspaper cited unions as suggesting that staff brought in to help relieve the pressure at Heathrow - which has faced recurring problems handling large influxes of passengers - weren't being properly trained. The airport, Europe's busiest, has recently struggled to clear huge lines which build up at immigration during peak times, leading to fears of Olympics-related chaos as tourists fly in to watch the games.

Meanwhile The Independent on Sunday newspaper reported that top Home Office officials had been warned by police nearly a year ago about the inability of G4S to provide enough staff, while the BBC quoted the chief of Britain's National Association of Retired Police Officers as saying that his group could have helped fill the shortfall in manpower - if only G4S had bothered getting in touch.

"With enough notice we could have provided a significant number (of retired officers)," he told the BBC. "They have made no effort to do that."

The British minister in charge of the Olympics appeared on a talk show Sunday to try to calm the uproar - noting that G4S boss Nick Buckles had apologized and would be footing the bill for the last-minute military deployment - as well as up to 20 million pounds ($31 million) for failing to live up to his company's end of the deal.

"I don't think this is a moment for getting into the blame game actually," Hunt told the BBC's "Andrew Marr Show." ''G4S has been quite honorable. They put their hands up. Nick Buckles, their chief executive has said they got it wrong. They've apologized. They're going to cover all the costs."

Hunt insisted that the government realized only last week that G4s would not be able to meet its targets and that it immediately activated its contingency plans.

"I think it's completely normal that you're going to find some contractors on a project of this size who aren't able to deliver what they've promised," he said, stressing that security for the games would not be compromised. "We have contingency plans for all eventualities."

London organizing chairman Sebastian Coe seemed to express sympathy with G4S, saying that "the reality is that it was only when the rubber hit the road that we were able to see, as G4S identified, a gap," he told BBC radio.

"This actually wasn't about supply. They (G4S) have been interviewing about 100,000 people. The reality is, and I cannot put this anymore simply, when they expected people to materialize, they simply didn't."