The European Union has lifted borders controls for citizens of nine of the newest EU member states.

People from the nine countries that joined the union in 2004 will be able to traverse most of the continent by road or sea without showing a passport or national ID card. Airports are scheduled to lift passport controls in April.

"I can define this as an historic event. Now, after the enlargement in 2004 we are granting European citizens from the new nine member states new freedom of movement, without controls, without showing passports," Franco Frattini, EU commissioner for freedom, justice and security, said in a telephone interview, according to the Los Angeles Times.

The Schengen agreement, which allows passport-free travel across the area, embraces now 24 nations. The Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia and Slovenia joined the zone. Portugal, Spain, France, Italy, Belgium, Luxemburg, the Netherlands, Germany, Austria, Sweden, Finland, Denmark, Greece and non-EU members Norway and Iceland are already members of the zone.

Britain and Ireland have not yet joined Schengen and new EU members Bulgaria and Romania are not yet allowed in.

As a condition for joining, the new members have to strengthen security on their borders with non-EU nations such as Ukraine, Belarus and Serbia.

The expansion of the Schengen zone will bring about 400 million people in the zone.

Many European leaders have welcomed the pulling down of internal frontiers as a new sign of the continent overcoming its Cold War division. On the other hand, many people have also expressed fears of increased crime and illegal immigration.

The Schengen agreement is named after the village in Luxemburg where it was signed in 1985 by France, Germany, Belgium, Luxemburg and the Netherlands to allow citizens to travel freely between them.