Terror threat from Europe could lead to stricter controls on travelling to America

The continent is increasingly seen as a platform for attacks, admitted Michael Chertoff, and that may mean tougher checks for Britons travelling to the States.

He explained that he had no plans to scrap the visa waiver programme but could force Britons and others to register online before travelling.

Scroll down for more

Mich "One of the things we've become concerned about lately is the possibility of Europe becoming a platform for a threat against the United States," he said in an interview with BBC World News America.

"That's for a couple of reasons. We have the visa waiver programme which allows most Europeans who come to be tourists to come without visas - that means the first time we encounter them is when they arrive in the United States and that creates a very small window of opportunity to check them out.

"Secondly is that we have watched the rise of home-grown terrorism. We are obviously mindful of the Madrid bombings, the attempted bombings in Germany, and that suggests to us that the terrorists are increasingly looking to Europe as both a target and a platform for terrorist attacks.

"So a lot of what we are trying to do is find a way to better vet people coming in from Europe without impeding the flow of travel or trade which has been a very important part of our economy."

He conceded that there was a "certain sense of complacency" about terrorism in the US, suggesting that the administration had been a victim of its own success in thwarting any attacks post 9/11.

"But when I lift my eyes and I look around the world and I look at what happens in Britain, in Germany, in Spain, in Bali, in Pakistan, I don't see terrorism going away; I see an al Qaida that's evolving," he added.

"I don't see any diminishment of the threat, and my concern is that we not relax and let the enemy get ahead of us."

The BBC also reported that a posting to a known Islamic extremist website talked about founding a branch of al Qaida in the UK and killing British politicians including Prime Minister Gordon Brown.