Summit security

Police and demonstrators have been flexing their muscles in the run-up to this week's summit celebrating the 60th anniversary of NATO.

German police have developed stringent plans for crowd control, after angry protests at the G-20 meeting in London descended into violent battles with police that saw one man collapse and die.

Police in the cities of Kehl and Baden-Baden, Germany, are expecting thousands of anti-NATO demonstrators at the April 3 and 4 meeting, which is being co-hosted by the French city of Strasbourg.

The head of the German police union told the Neuen Osnabruecker Zeitung: "We have to assume that protests against the NATO summit will be significantly more aggressive than in the past."

Early clashes

Moreover, he warned that there is a circle of people who abuse opportunities for peaceful protests "as an exuse to riot and brutally attack police".

First clashes took place on Tuesday night, April 1, when some 150 anti-NATO campaigners fought with police on the outskirts of Strasbourg.

Police used tear gas to disperse the protesters, who had gathered to voice their anger at the strict identification checks aimed at preventing troublemakers from disrupting the summit.

Meanwhile, across the Rhine river in Germany, four protesters were detained on Monday when 2,500 people turned up for an anti-NATO rally organized by left-wing groups.

Security officials are taking no chances ahead of the NATO summit, which is expected to see the 28-member alliance unveil a new strategy for the war in Afghanistan.

Beefing up the security detail

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

Police are reckoning with around 20,000 protesters on the German side alone. Of them, 3,000 are seen as potentially violent militants.

The situation is even more serious for the French. A police official told news agencies: "We've got the camp where anti-NATO campaigners are staying and are also host to the assembly of the NATO leaders. The Germans don't have that."

Protesters have registered 13 separate demonstrations in the two summit locations in Germany. They have also threatened to block roads and carry out other acts of civil disobedience.

Shipping along the Rhine will be halted on Saturday morning when the heads of state and government pose for photographs on a bridge linking Strasbourg to the German side.

Preparing for a Merkel-Obama stroll

In Baden-Baden, police have erected security zones around key venues, including the hotel where Chancellor Angela Merkel is staying and the building where the leaders will hold their opening dinner on Friday evening.

Manhole covers have been welded shut and parking metres were removed from some city center locations as a precaution against terrorist attacks with explosives.

People in flats overlooking the town square have been told to keep their windows closed and refrain from using their balconies when Merkel takes a stroll there with US President Barack Obama on Friday afternoon.