extremists

Under the current system, nations including Britain and Ireland can travel to the US without a visa for stays of 90 days or less.

However, Senator Feinstein has argued that the law has made it easier for terrorists to enter the country.

"There's no question in my mind that the visa waiver programme is a weak link in our efforts to keep violent extremists out of the country and it needs to be tightened up," she said.

The attack against satirical magazine Charlie Hebdo in Paris last month have sparked the recent debates over the visa waiver system.

The White House also expressed the view that change was needed, with counter- terrorism chief Lisa Monacco saying western passport holders were "of particular concern".

She went on to say that western tourists are "a very potent mixture and pose a potential threat, if left unchecked, to the homeland".

However, the move to change the law has been strongly criticised by US Homeland Security Secretary Jeh Johnson, who said it would be an error to scrap the "valuable" agreement which applies to citizens from 38 approved countries.

MISTAKE

"The visa-waiver programme is an important, valuable programme. There are some out there who want to scrap it, but I think that's a big mistake," he said.

Some tightening of security has already occurred with changes to the US electronic system for travel authorisation.

Since last November, tourists have been asked for more passport information and details of any other names or aliases they may have had.

hnews@herald.ie