Soldiers killed hundreds of Shiite Muslims this weekend after their group stoned the convoy of Nigeria's army chief, the Shia Islamic Movement and witnesses said Monday. Other reports put the number of dead at about 20.

The dead from the military raids include the wife and two sons of the movement's leader, Ibraheem Zakzaky.

Zeenah Ibrahim, the wife, was shot and killed on Sunday, witnesses said, hours after she called The Associated Press to report that soldiers were besieging her home in a "pre-planned attack to assassinate the sheikh," her husband.

The killings happened in Zaria, a town in northern Nigeria.

Witness Ojo Momodu said the Shiites barricaded the road with burning tires as Gen. Tukur Buratai approached and then stoned his convoy.

Army spokesman Col. Sani Usman called the stoning of Buratai's convoy "a deliberate attempt to assassinate."

Before she was killed, Ibrahim had said hundreds of Zakzaky's followers surrounded the house to protect the leader, whose whereabouts are not known.

Ibrahim said the military has targeted the movement in the past, and last year killed three of her sons who had come home from studies in Beijing and Beirut for a religious procession.

Movement spokesman Ibrahim Musa said the military retaliated to the stoning incident with "indiscriminate killing." His statement, received Monday said, "The killing was so brutal at Gyallesu (one of the areas of Zaria where the group has a spiritual center) that even those injured in the shooting were identified and killed in cold blood by the soldiers."

Reports from human rights activists and Nigerian newspapers said about 20 people were killed.

It was impossible to independently verify the toll as the military Monday continued a lockdown preventing access to three "husainiyya," or spiritual centers.

The Shiites two weeks ago suffered a suicide bombing by Boko Haram extremists that killed 22 people. Boko Haram often attacks Muslims who preach against its radical vision of Islam.

In 2009, Nigerian armed forces attacked Boko Haram's headquarters and killed about 700 people, including its leader. The group then re-emerged as a much more violent entity.