In nightly sermons broadcast on the Internet, Sheik Omar Bakri Muhammad, a 46-year-old Syrian-born cleric, has urged young Muslim men all over the world to support the Iraq insurgency on the front line of "the global jihad," investigators say.
He struck a similarly defiant tone this month at a rally attended by 500 people at a central London meeting hall, where a giant screen behind him showed images of the World Trade Center falling. "Allah akbar!" - "God is great" - some audience members shouted at the images.
After eavesdropping for months on his nightly praise of the Sept. 11 hijackers and of suicide bombings, Scotland Yard said last week that it was investigating Sheik Omar, the leader of Al Muhajiroun, Britain's largest Muslim group, and officials are exploring whether they can deport him. "We're fed up with him," said a senior British official, who spoke on condition of anonymity. "He needs to be stopped, or he needs to go."
The more aggressive approach toward Sheik Omar is part of an increasing effort to monitor and restrict militant imams in Britain and across Europe. Authorities have stepped up surveillance of militant mosques in several countries, including Germany and France. French officials deported an imam this month after officials said he was inspiring men to join the jihad.
One major concern, officials say, is that more heated religious rhetoric is encouraging young men to leave home to fight in Iraq.
Although the dimensions of the recruitment effort from Europe to Iraq are not clear, there are indications that it is intensifying.
On Sunday, the German police arrested a man suspected of being a member of Al Qaeda and charged him with recruiting men to carry out suicide bombings in Iraq. These arrests were part of an ongoing investigation in cooperation with the United States of recruitment and other terrorist activities in Europe. A senior German official said he was certain there would be additional arrests of militants inside the country who have set up sophisticated recruitment and smuggling networks that lead to Iraq.
Italian investigators say several recruits from Italy carried out bombing attacks in Baghdad. Swiss officials say they are concerned that several militant clerics have openly urged men to become terrorists. And in Jordan, senior officials say they have recently arrested several dozen men who intended to cross the Iraqi border to serve as foreign fighters.
Bohre Eddine Benvahia, the 33-year-old imam recently deported by France to Algeria, had urged young men in a working-class neighborhood of L'Ariane, outside Nice, to join jihad, French intelligence officials said.
Sheik Omar did not return repeated phone calls over the past several days. Last week, he denied in several interviews that he had urged people to become foreign fighters in Iraq, saying his comments had been taken out of context.
"I believe Muslims are obliged to support their Muslim brothers abroad - verbally, financially, politically," he told The Associated Press. "I never said, 'Go abroad.' But if people want to go abroad, it's a very good thing to do. But we never recruit people to go abroad."
News of the central London rally, which was first reported by United Press International, and portions of Sheik Omar's nightly Internet sermons, have alarmed senior British officials. In one sermon last week, Sheik Omar called Al Qaeda "the victorious group" that he said Muslims were "obliged" to join.
Home Secretary Charles Clarke has asked officials to investigate whether they can help relocate Sheik Omar to Syria or Lebanon.
Like their counterparts in Britain, counterterrorism officials in Germany say they have seen indications of an increase in attempts by groups there to recruit young fighters to travel to Iraq to fight. Some men in recent weeks have planned to go to Iraq to carry out suicide bombing missions, the officials said.
In the arrest on Sunday, prosecutors said a man they identified as Ibrahim Mohamed K., a 29-year-old Iraqi from Mainz, Germany, had persuaded a 31-year-old man, Yasser Abu S., to go to Iraq on a suicide bombing mission.
Prosecutors said Yasser Abu S. intended to fake his death in a car accident in Egypt and use the life insurance proceeds to pay for Qaeda activities in Germany and travel expenses to Iraq, where he planned to carry out a suicide bombing. The surnames of suspects in criminal cases are not disclosed in Germany.
"Stopping recruitment for Iraq where they may do harm to U.S. troops is our highest priority, and the Germans and other European governments are cooperating," a senior American counterterrorism official based in Europe said in an interview with The New York Times and the PBS program "Frontline." He said a would-be suicide bomber intending to travel to Baghdad was arrested early last fall in Germany. German officials said they were worried that recruitment had intensified there in recent months.
Last October, the International Institute for Strategic Studies estimated that 1,000 "foreign fighters" had entered Iraq to join the insurgency, although American military officials in Iraq have acknowledged that they are unsure of the numbers of outside fighters.
In raids in several German cities on Jan. 12, the German police arrested 22 people suspected of being militant Muslims while recovering dozens of forged passports and boxes of militant propaganda. A senior German law enforcement official, who spoke on condition of anonymity, said many of the arrested men were members of Ansar al-Islam, recruiting young men to go to Iraq. "One of their projects was to recruit, but they also were smuggling people to Iraq," the official said. He declined to say how many people were estimated to have left Germany for Iraq.
Counterterrorism officials view some militant European mosques as a link in the Iraq recruiting chain, just as they came to see the importance of Al Quds mosque in Hamburg in the formation of the Qaeda cell led by Mohamed Atta, the leading hijacker in the Sept. 11, 2001, attacks in the United States. Senior officials say that in addition to their concern about European fighters going to Iraq, they also fear that the Iraq war has increased the possibility that terrorists might single out European countries, particularly Britain and Italy, whose leaders have not wavered in supporting the war.
Officials say that in some countries, their efforts to control activities at mosques are hampered by laws that protect religious expression and restrict what they can do to stop hateful speech. British officials say that if they want to deport an imam who they fear is inciting violence, the proceedings can often take months or even years. Under Britain's Terrorism Act of 2000, prosecutors can charge clerics for using "threatening, abusive or insulting behavior" to incite racial hatred.
In Britain, where 1.8 million Muslims live, elected officials are demanding that the police move quickly against several imams who they say have become far more vocal in recent weeks.
Sheik Omar, who was lived here since 1985 after he was deported from Saudi Arabia, warned that Britain must scale back its antiterrorism laws or it would face a "horrendous" response from angry Muslims. "I declare we should ourselves join the global Islamic camp against the global crusade camp," he said.
It is not just imams who have become outspoken in exhorting young men to become jihadists. At the rally sponsored by Sheik Omar, a young speaker named Abu Yahya Abderahman said: "We are at war. It's time for brothers, sisters and children to prepare. Prepare as much as you can, whether they are sticks or stones or bombs. Prepare as much as you can to defeat them, to terrorize them."
In the months after Sept. 11, diplomatic pressure built for Britain to move against outspoken imams. But it was not until last May that British officials arrested the most high-profile militant cleric, Abu Hamza al-Masri of the Finsbury Park mosque in north London. He was charged with soliciting or encouraging others to murder people who did not believe in the Islamic faith.
Mr. Masri also faces extradition to the United States, where he is charged with 11 terrorist counts, including trying to establish a terrorist training camp in Oregon. The Finsbury Park mosque was attended by Zacarias Moussaoui, now facing Sept. 11 terrorist charges in the United States, and Richard C. Reid, the so-called shoe bomber.
Now leading the mosque is another militant Muslim, Abu Abdullah, who said in an interview, "People see us as extremists because we don't compromise the religion of Allah."
Last month, the United Nations placed sanctions against Saad Fagih, a Saudi dissident living in London who is the leader of the Movement of Islamic Reform in Saudi Arabia. Mr. Fagih adamantly denies that he has any ties to Al Qaeda, but British officials say they are concerned about his activities, too.