Strasbourg, France  - Twelve people were arrested after violent anti-NATO protests in the French city of Strasbourg on Thursday, one day before leaders from the
28-member alliance were due to meet there, a police spokesman said.

Demonstrators hurled rocks, broke windows and set trash bins on fire before police fired tear gas canisters and order was restored.

The demonstration turned violent after police prevented some 600 protesters from marching into downtown Strasbourg.

Germany and France have both launched major security operations to keep order during the two-day summit, which marks the 60th anniversary of NATO's founding. Parts of the summit will also take place in the German town of Kehl and the city of Baden Baden, across the French border.

Some 14,600 police will be guarding the 3,500 delegates on the German side, while 10,000 will be patrolling the streets of Strasbourg, where most of the talks will be held.

German security officials said they expected up to 25,000 demonstrators to turn up in Germany, around 3,000 of whom have been classified as potentially violent. dpa