France stepped up its defenses against terrorist attacks this week, amid growing fears that Europe has become the most likely target for al Qaidas next attack. Prime Minister Jean-Pierre Raffarin said he would mobilize the entirety of state services to ward off terrorism, including doubling an antiterrorism unit to 800 soldiers. In Germany this week, Interior Minister Otto Schily said the threat of terrorism in Europe was as great as at any time since Sept. 11. The warnings reflect a change in Europes perception of its vulnerability since October, when top al Qaida strategist Ayman al-Zawahiri called on holy warriors to attack the Continent. In a recent audio tape, Osama bin Laden also warned that Europe would be attacked. The threat is much wider than al Qaida, said French terror investigator Jean-Louis Bruguière. It is like a spreading cancer. Europe has a substantial Muslim immigrant population, and many of these immigrants sympathize with al Qaidas anger at the West.