By Robin Pomeroy

ROME, July 22 (Reuters) - A Moroccan imam arrested in Italy and suspected of running a "terrorism school" in his mosque had a variety of toxic chemicals at his home which could have been used to make explosives, police said on Sunday.

The imam was arrested in a dawn swoop on Saturday along with two assistants who worked in the mosque at Ponte Felcino, near the central Italian city of Perugia. Police seized films and Internet files they said were used for combat training.

At the house of the imam, identified as Korchi El Mustapha, police said they found "dozens of bottles" inside three barrels containing a variety of chemicals "with which, when combined and mixed with other easily available products, it would be possible to make improvised explosives."

The arrests shocked Italy which, unlike Britain and Spain, has not experienced attacks by Islamic extremists, and Sunday newspapers carried headlines like "Al Qaeda school in Perugia" and "Terrorists ready to strike".

Police, who searched 23 addresses in the area, said the mosque was being used to recruit and train international terrorists.

The imam of Perugia, Abdel Qader, told the Rome daily Il Messaggero that he condemned anyone who preached violence and that the 10,000 Muslims living peacefully in the city were "a concrete example of successful cohabitation".

Qader said he had met the arrested imam and had no reason to suspect him of militancy, but did not know him well. "Perhaps sometimes he polemicised about international affairs, but you know how words can fly," he said.

The head of Perugia's Muslim community said he hoped there would not be a backlash against the faith, though this has already started in some quarters.

Roberto Calderoli, an opposition member of Italy's upper house for the anti-immigration Northern League, said all Italy's mosques should be closed and allowed to reopen only after they had been checked for illegal activity.

"As we don't know where's the baby and where's the bathwater, the only thing to do is to close all the mosques and reopen them only after accurate inquiries and checks," he said. (Additional reporting by Massimiliano Di Giorgio)