The US has said that only travellers using ePassports which store biometric data are permitted to use the country's visa waiver programme.The Department of Homeland Security announced the change on Thursday as part of plans to bolster security measures from countries whose citizens are allowed to travel to the United States without a visa.Thirty-eight countries, mostly from Europe, participate in the Visa Waiver Program. Citizens of those countries can travel to the U.S. visa-free for periods of up to 90 days. However, under the new rules anyone arriving from there must have electronic passports capable of employing biometric-recognition technologies such as fingerprinting.”The security enhancements we announce today are part of this department's continuing assessments of our homeland security in the face of evolving threats and challenges, and our determination to stay one step ahead of those threats and challenges,” said DHS Secretary Jeh Johnson. “And it is our considered judgment that the security enhancements we announce today will not hinder lawful trade and travel with our partners in the Visa Waiver Program.”