Police hunting Islamic militants across Europe have launched a dramatic series of anti-terror raids in three countries over the past 36 hours.
One of the raids led to the arrest of a suspected Algerian extremist in the German port of Hamburg.
Mr Abderrazak Mahdjoub (29) was held at the request of Italian authorities investigating an alleged network involved in recruiting Islamists to carry out suicide attacks in Iraq.
The arrest warrant shows one of the recruits was suspected of complicity in an October rocket attack on a Baghdad hotel where US Deputy Defence Secretary Paul Wolfowitz was staying.
Four other North African suspects - three from Tunisia and one from Morocco - were arrested in northern Italy on Thursday in connection with the same investigation.
"We're talking about true combatants who have come back from missions and are in constant movement, looking for extremists prepared to carry out suicide attacks," one Italian investigative source said.
The suspect are expected to be charged with "subversive association for international terrorism" under a law Italy introduced after the September 11 attacks.
Separately, British police are still questioning a suspected would-be suicide bomber who authorities believe could have links with al Qaeda. They also made six arrests in Birmingham and carried out raids in Gloucester where the suspect arrested on Thursday was detained.
The Europe-wide operations coincided with the charging of three Kenyans in connection with a previously undisclosed plot to blow up the US embassy in Nairobi - the same mission that was destroyed by suspected al Qaeda bombers in 1998.
While described as breakthroughs, the developments highlight indicate the level of concern in Europe about Islamic radical activity in the wake of deadly suicide attacks in Saudi Arabia and Turkey this month.
In the latest alert, the NATO-led peacekeeping force in Kosovo said on Friday it had stepped up security in response to a "specific threat" against international organizations in the UN-run province.
Two years into the US-led "war on terror", some European security officials are concerned Islamic militants may be drawing new strength from Muslim anger over the occupation of Iraq.
German foreign intelligence chief Mr August Hanning last week described Iraq as a potential "crystallizing point" for the radical Islamist cause and said small numbers of activists had been heading there from several European countries with the aim of fighting the U.S. occupation.
Germany has been especially vigilant for signs of extremism in its 3.2 million-strong Muslim population since the September 11 attacks on the United States. Three of the 19 suicide hijackers had lived and studied for years in Hamburg.