Ali Shah Nehmat, the imam at Norway's largest mosque, was seriously wounded in an ax attack on Monday night. The imam in his 60s was attacked from behind with a small ax in the street outside his home when he was on his way to the mosque run by Jamaat-e Ahl-e Sunnat, according to Norwegian press reports.

The imam was rushed to hospital with serious wounds on the face. At 1:15 a.m. local time on Tuesday (1115 GMT Monday), he remained unconscious, but his condition was reportedly stable after surgery, said sources close to the imam.

"The condition was life threatening when he came to the Ullevaal hospital, but is now stable," said Rune Ullsand, an Oslo police officer.

A police investigation was going on to find the perpetrator. Police patrols were more visible in Oslo in search of the attacker.

The Jamaat-e Ahl-e Sunnat, which was founded in 1977, has more than 5,000 members, mostly first-generation immigrants from Pakistan.

The mosque, which is situated at Gronnland of Oslo, was opened in 2006 with a capacity for about 2,500 worshippers.

About 1.5 percent of the 5 million residents in Norway are Muslims. In Oslo, most Muslims live in the east of the city, including Gronnland.