Access to passenger data remains a contentious issue
President George W Bush has announced that the United States is to cancel visa requirements for citizens of six European countries and South Korea.
Mr Bush said Latvia, Estonia, Hungary, the Czech Republic, Lithuania, Slovakia and South Korea would be added to the US visa waiver programme in a month.
The countries already allow US citizens to visit without requiring a visa.
Access to personal data was a key consideration. Since the 2001 terror attacks the US has tightened its rules.
The US requires that members to its scheme issue their nationals with tamper-proof biometric passports, which are difficult to forge.
The waiver programme was initiated in 1986 "with the objective of eliminating unnecessary barriers to travel, stimulating the tourism industry," according to the State Department website.
The visa waiver programme has been under fire from some US lawmakers, who are concerned that militants who are citizens of the participating countries can obtain entry too easily.