Reuters: Four people were killed and a dozen were injured in northwestern Iran when police attacked the hideout of an extremist Shia Muslim religious group, an interior ministry official said on Wednesday. Reuters

TEHRAN - Four people were killed and a dozen were injured in northwestern Iran when police attacked the hideout of an extremist Shia Muslim religious group, an interior ministry official said on Wednesday.

Members of the group, which authorities did not name, attacked police on Tuesday near the northwestern city of Miandoab, an official in the city told Reuters by telephone.

The group, whose leader Seyyed Agha Nezam claims to be the last imam of Shi'ite Muslims, has repeatedly caused civil disorder in Miandoab, the source said.

Shi'ite Muslims believe their 12th and last imam Mahdi, who went into hiding in the year 874, will return to earth one day to usher in an era of perfect justice.

"Three members of the group and one police officer were killed during the fight," said the official who declined to be named. "The leader of the group managed to escape."

At least 12 police officers were injured and some eight gang members were arrested.

Police seized a large amount of weaponry including rifles and hand-grenades when they entered the group's hideout near Miandoab, city governor Hamid Shokri was quoted by student news agency ISNA as saying.

Clashes between Iranian authorities and extreme religious groups are rare.