Kolkata, where gunmen shot dead four police this week outside the American Center, has stepped up security for Republic Day parade on Saturday, banning spectators from bringing cameras or cellular telephones, officials said. "A red alert has been sounded across the state and over 13,000 policemen will be on duty in Kolkata during the Republic Day parade," Police Deputy Commissioner Banibrata Basu said.

All police at the parade have been asked to pin identity cards to their uniforms and stop spectators from bringing in mobile telephones, cameras, pagers, binoculars or any bags, Basu said. Police have also set up sandbags to guard the sprawling parade ground at Fort William, a key monument in the city.

Unidentified gunmen on a motorbike Tuesday morning opened AK-47 fire outside the American Center on several dozen police guards, killing four of them.

More than 70 people have since been picked up for questioning, with about a dozen Muslims arrested. US officials have questioned whether the Center was the prime target, pointing out that no attempt was made to enter or damage the building. Some investigators believe the attack's prime target was the police.

In New Delhi, nearly 50,000 police and paramilitary personnel will be on duty for the 53rd Republic Day to prevent attacks on the celebrations, which will be attended by the country's top officials. Bureau Report