STRASBOURG, France (Reuters) - Riot police clashed with hundreds of protesters on Thursday ahead of a NATO summit of world leaders, firing repeated rounds of tear gas and rubber bullets to try to disperse the crowds.
About 200 youths were arrested and police say they fear there could be much more violence over the next two days both in France and nearby Germany, which are co-hosting 60th anniversary celebrations for the military alliance.
More than 500 demonstrators tried to converge on the center of the French city of Strasbourg in a spontaneous protest during the afternoon, their numbers swelled by disaffected youths from the surrounding suburbs.
They smashed windows, vandalized cars and barricaded a street before being pushed back out of the city by police.
At one point, rioters charged a military vehicle that happened to cross their path, with a masked youth hurling a pole through the windshield.
One of the occupants, who was in uniform, drew his gun and pointed it toward the sky, giving the driver time to speed off.
Organizers of the anti-NATO movement, which has set up camp just outside Strasbourg, condemned the violence.
"We have no sympathy for the vandalizing," Reiner Braun, one of the group leaders, told Reuters.
Reuters reporters said there was a fierce confrontation near the camp in the evening, with youths hurling stones at security forces who responded with a barrage of tear gas and rubber shot, forcing them back into their tented village.
Protest groups have said they want to bring chaos to the NATO summit and police warn that clashes at the G20 meeting in London earlier this week have fueled tensions.
U.S. President Barack Obama is due to arrive in France on Friday morning and will take part in two events in Strasbourg before traveling to Baden Baden, just across the German border.
About a hundred people staged a peaceful demonstration in Baden Baden, calling on nations to spend less on defense and more on fighting poverty.
Security forces tried to restrict access to Strasbourg and Baden Baden on Thursday, with helicopters circling overhead, crowd barriers strung along the streets and hundreds of police patrolling the highways.
German police said they feared violent confrontations on Friday when the NATO meeting formally begins in Baden Baden, Some 20,000 protesters are expected.
Rainer Wendt, head of German police trade union DPolG, said the situation had grown more tense following the death of a man at protests in London on Wednesday night against the G20 summit.
"We've seen that it just takes 24 hours and you can already read on the Internet that police are apparently to blame. People wind each other up," he told Reuters.
British police are investigating the circumstances surrounding the death, saying only that the man collapsed in the street and was found unconscious.
Youths defying police in Strasbourg had all heard about the death. "Stop repression in London and Strasbourg," read one banner on Thursday.
(Additional reporting by Sophie Hardach in Strasbourg and Kerstin Gehmlich and Madeline Chambers in Berlin)
Writing by Crispian Balmer; Editing by Matthew Jones