Last week’s terrorist attacks in Paris could lead to a further tightening of the US visa waiver programme, used by more than 19 million visitors a year.
Senator Dianne Feinstein this week described the programme as ‘the Achilles heel of America’ and called for it to come under scrutiny.
She said there was a danger that terrorists could go abroad for training and enter the US via a country from where they wouldn’t need to apply for a visa.
Citizens of several countries, including the UK, can enter the US for up to 90 days without visas, although they are required to fill out a visa waiver form online.
"I think there are sleeper cells, not only in France, but certainly in other countries, and, yes, even in our own," said Feinstein, a former chair of the Senate Intelligence Committee. "I think we need to take a look at the visa waiver program again, and see what we can do to prevent this kind of thing from happening, because I believe it will happen, if it hasn’t already."
The program has been an effective tool in promoting business and leisure travel to the US.
A congressional report said 19.1 million people used the program in 2012, representing 40% of all overseas visitors.
