DUBAI: Bahrain police have arrested Ali Salman, head of the main Shiite opposition bloc Al-Wefaq that has spearheaded protests against the authorities in the Sunni-ruled kingdom, the group said on Saturday.

“Al-Wefaq can confirm that Sheikh Ali Salman has been arrested,” it said in a brief statement.

“He is in detention after a series of illegal measures which comprised summonsing him to the office of criminal investigation and bringing him before a public prosecutor,” the statement added, without elaborating.

There was no immediate word from the authorities on the reported arrest.

In a separate statement, Al-Wefaq said supporters of Salman were gathering outside his home after hearing of his arrest.

It said they were holding up pictures of the group’s leader and “demanding his immediate release”.

Al-Wefaq, the most important opposition grouping in Shiite-majority Bahrain, wants a constitutional monarchy in the Gulf nation ruled by the Al-Khalifa dynasty.

It repeatedly says it rejects violence, but the authorities in turn blame its supporters for the trouble that has shaken the country.

A month-long protest that erupted on February 14, 2011, was dispersed in a mid-March deadly crackdown helped by security forces from neighbouring Saudi Arabia.

At least 89 people have been killed in Bahrain since the Arab Spring-inspired protests erupted, according to the International Federation for Human Rights.

Demonstrators frequently clash with security forces in Shiite villages outside the capital Manama.

Bahrain, a strategic archipelago just across the Gulf from Shiite Iran, is the home base of the US Fifth Fleet and Washington is a long-standing ally of the ruling Sunni dynasty.