The Czech president, Vaclav Havel, last night signed into law a bill handing responsibility for his country's security to the Pentagon during the two-day NATO summit next week, amid mounting fears of terrorist attack and street violence.

Prague police have arrested five Czechs, at least two of them teenagers, on suspicion of plotting sabotage during the first NATO meeting of its kind since George Bush came to power - and the first since the September 11 atrocities.

The first detachments of an estimated 250 US troops are expected in Prague today to play a central role in ensuring security during the summit, which will inevitably have its agenda hijacked by the preparations for war on Iraq.

The initial agenda concentrated on the "transformation" of NATO, in which up to seven new members from the former Soviet bloc would be admitted to the alliance.

US F-15 and F-16 fighter aircraft will patrol the skies over the Czech Republic throughout the summit next Thursday and Friday.

The Americans are to deploy at least 10 fighter aircraft, using an air base 50 miles south of Prague. Under special legislation rushed through the Czech parliament, the US troops and aircraft will be under US command. But the Czech government, in the person of the defense minister, has to give the green light for any US use of force.

Mr Havel cut short a holiday in the Canary Islands, where he was recuperating from bronchitis, to sign the bill last night after it was endorsed by the Czech senate. The bill passed parliament's lower house by a large majority last week.

Thousands of anti-globalization protesters turned central Prague into a battlefield during the International Monetary Fund and World Bank summit in the city two years ago. The Czech authorities and the Americans appear determined to prevent a repeat performance now when tensions are greater because of the Middle East crisis and widespread warnings of imminent al-Qaida attacks in Europe.

The five arrested yesterday were Czechs, including two 19-year-olds from Ostrava, 200 miles east of Prague. A police spokeswoman described them as "extremists" and claimed they were plotting to disrupt power supplies in Prague and in the underground metro system during the summit.

The police have also been given powers to arrest any masked demonstrators who decline a request to show their faces.

An umbrella group of four anti-globalization organizations called "Anti-NATO" is preparing for protests against the summit delegates, who include 46 heads of state, almost 3,000 delegates and a 3,000-strong media entourage.

Police expect 12,000 people to protest on the streets; they will be matched by similar numbers of security services personnel.

A senior police official said he expected at least one in five protesters to be violent. Around 2,000 foreign protesters have been blacklisted and will be prevented from entering the country.

Wenceslas Square, the city center avenue where the great drama of 1989's velvet revolution was enacted, will be the central venue for the protests which are scheduled to start on Sunday.

© Guardian Newspapers Limited 2002

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