The International Association of Chiefs of Police, which represents the heads of police forces across the world, has issued guidelines saying that officers who confront a suicide bomber should shoot the suspect in the head.

The recommendations, the first from a major police organization to deal with the realities of a post-September 11 world, take a more aggressive posture than typical lethal-force guidelines.

The guidelines were circulated July8 - about two weeks before the London police, acting on such a policy, killed a innocent Brazilian. They shot him in the head because they mistook him for a suicide bomber.

The National Bomb Squad Commanders Advisory Board in the United States is developing the first national protocol for response to suicide bombers and is also recommending to police bomb squads nationwide that if a suspect is wearing a suicide bomb, an officer who needs to use deadly force should not shoot near the bomb.

US police officers and federal agents typically have been authorized to use deadly force if lives are in imminent danger. But since the September 11, 2001, terror attacks, the definition of imminent danger has changed, prompting law enforcement officials to rethink the rules of engagement.

``There is not a responsible chief or head of a law enforcement agency in this country who isn't now pondering the dilemma a suicide bomber presents to their officers,'' said US Capitol Police Chief Terrance Gainer, who became the first chief in the nation to adopt a shoot-to-kill policy if his officers are confronted with a suicide bomber.

After the July 7 attacks on the London transit system by suicide bombers, the international police chiefs' organization produced a detailed training guide for dealing with suicide bombers for its 20,000 law enforcement members. It recommends that if an officer needs to use lethal force to stop someone who fits a certain behavioral profile, the officer should ``aim for the head'' to kill the person instantly and prevent the setting off of a bomb if one is strapped to the person's chest.

The police organization's behavioral profile says such a person might exhibit ``multiple anomalies,'' including wearing a heavy coat or jacket in warm weather or carrying a briefcase, duffle bag or backpack with protrusions or visible wires. The person might display nervousness, an unwillingness to make eye contact or excessive sweating. There might be chemical burns on the clothing or stains on the hands. The person might mumble prayers or be ``pacing back and forth in front of a venue.''

The police group's guidelines also say the threat to officers does not have to be ``imminent,'' as police training traditionally teaches. Officers do not have to wait until a suspected bomber makes a move, another traditional requirement for police to use deadly force.

An officer just needs to have a ``reasonable basis'' to believe that the suspect can detonate a bomb, the guidelines say.

Last year, Gainer retrained his officers to shoot to kill when faced with a suspected suicide bomber who is uncooperative and refuses to stop and be searched. Other law enforcement officials say they are debating the issue and might follow his lead if there is a suicide bombing in the United States.

In Israel and Britain, countries with a history of confronting terrorist violence, police have adopted a national policy of shooting a suspected suicide bomber in the head to prevent detonation of a suicide vest. The British order became public last week after the shooting of the Brazilian.

Gainer retrained his officers after a trip to Israel during which he and other chiefs traveled with the Police Executive Research Forum for week-long counterterrorism schooling from Israeli officers familiar with confronting Palestinian suicide bombers.

The Israeli training of British and American law enforcement officials makes some groups ask whether the police are going too far.

The tension is especially pronounced among Muslim community leaders, who are deeply suspicious of Israel because of the conflict with the Palestinians.

``The London situation where an innocent man was shot and killed was based on Israeli procedure, and I don't think that we want to be replicating the actions of a foreign government engaged in a brutal occupation of another people,'' said Ibrahim Hooper, spokesman for the Council on American-Islamic Relations.

In contrast to the national shoot-to-kill policies of Israel and Britain, American use-of-force orders are set by each of the nation's 18,000 law enforcement agencies.

A number of high-profile shootings in the past decade, including that of Amadou Diallo, who was shot 41 times in 1999 by New York police officers, highlighted the abuse of lethal force by out-of-control officers and the deadly mistakes that can be made by fearful or reckless police.

THE WASHINGTON POST