The United States says it will begin in September to require visitors from all countries except Mexico and Canada to be digitally fingerprinted and photographed when they enter the country. Nearly 30 countries, mainly in Europe, had previously been exempt from the security requirements.

Travelers from the 27 countries covered by the State Department's "visa waiver program," including key U.S. allies like Britain, Japan and Australia, will still to able to enter the United States without having to apply for U.S. visas at home.

But as of September 30, they will have to submit to the digital fingerprint and photo requirements, which have been controversial and prompted, in the case of Brazil, the imposition of similar formalities for Americans entering that country.

The State Department announced the change Friday in conjunction with a request to Congress to extend for two years a deadline for countries in the visa waiver program to begin issuing high-tech passports.

Those travel documents will contain computer chips that will include fingerprint and other identity information that will make them almost impossible to counterfeit, but many of the countries in the waiver program have encountered difficulties in introducing them.

The tighter U.S. passport rules stem from 2002 legislation increasing border security in the aftermath of the 9/11 terrorist attacks in New York and Washington.

At a news briefing, State Department spokesman Adam Ereli said the additional entry formalities in September should not pose undue inconvenience to affected visitors and are by no means intended as a slap to U.S. allies.

"If that's the way it's seen, then it's certainly not intended in that light," he said. "We are not requiring visas. We are requesting a two-year extension. I think that is recognition that the program has a value and the program is important. At the same time, there are security needs. I think everybody recognizes those security needs, and the US VISIT program is a very, very low-hassle un-intrusive way of protecting the public and protecting the United States."

Officials here say the digital photos and the scanning of visitors' two index fingers at immigration booths at U.S. air and sea ports adds less than a half-minute to entry formalities.

They say about five million people have been processed since the requirements took effect in January, and that hundreds of people suspected of criminal or immigration violations have been prevented from entering.

Congress had set an October deadline for visitors from the visa-waiver countries to begin using the "biometric" passports or lose the privilege of entering the United States without a visa.

Secretary of State Colin Powell and Homeland Security Secretary Tom Ridge warned legislators last month of "grave consequences" if the deadline was not extended.

They said U.S. embassies in the 27 countries would have been overwhelmed by visa paperwork, and the American tourism industry could have faced billions of dollars in losses as would-be U.S. visitors opted not to deal with visa applications and went elsewhere.