DUBAI (Reuters) - Saudi Arabia’s grand mufti, the top religious authority in the birthplace of Islam, has condemned Nigeria’s Boko Haram as a group “set up to smear the image of Islam” and condemned its kidnapping of over 200 schoolgirls.

Sheikh Abdulaziz Al al-Sheikh said the radical movement, which says it wants to establish a “pure” Islamic state in Nigeria, was “misguided” and should be “shown their wrong path and be made to reject it.”

His remarks came as religious leaders in the Muslim world, who often do not comment on militant violence, joined in denouncing Boko Haram leader Abubakar Shekau for saying Allah had told him to sell off the kidnapped girls as forced brides.

“This is a group that has been set up to smear the image of Islam and must be offered advice, shown their wrong path and be made to reject it,” he told the Arabic-language newspaper al-Hayat in an interview published on Friday.

“These groups are not on the right path because Islam is against kidnapping, killing and aggression,” he said. “Marrying kidnapped girls is not permitted.”

Boko Haram militants kidnapped some 250 girls on April 14 from a secondary school in Chibok village, near the Cameroon border, while they took exams. Fifty have since escaped.

Shekau’s video was released on Monday, sparking a wave of revulsion in Nigeria and abroad and prompting offers of help from countries such as the United States, Britain and France to search for them.

Boko Haram has led a five-year-old insurgency with the stated aim of reviving a medieval Islamic caliphate in modern Nigeria, whose 170 million people are split roughly evenly between Christians and Muslims.

Its violent attacks have become by far the biggest security threat to Africa’s top oil producer and it has spread out to menace the neighboring countries of Cameroon, Niger and Chad.

On Thursday, Islamic scholars and human rights officials of the Organization of Islamic Cooperation, the world’s largest Muslim body representing 57 countries, denounced the kidnapping as “a gross misinterpretation of Islam”.

This week, Al-Azhar, the prestigious Cairo-based seat of Sunni learning, also said that the kidnapping “has nothing to do with the tolerant and noble teachings of Islam.”