The wife of a Shiite leader says soldiers have killed at least 12 people in an ongoing siege of an Islamic movement accused of trying to kill Nigeria's army chief.

Zeenah Ibrahim says dozens of people are wounded in an attack by soldiers that began late Saturday at her home in the northern Nigerian town of Zaria.

Army spokesman Col. Sani Usman says hundreds of Shiites were carrying "dangerous weapons" Saturday afternoon and some fired on the convoy of Gen. Tukur Buratai in "a deliberate attempt to assassinate" him.

Ibrahim says soldiers later surrounded her home in a "pre-planned attack to assassinate the sheikh," Ibraheem Zakzaky.

His movement two weeks ago suffered a suicide bombing claimed by Boko Haram extremists that killed 22 people.

Zakzaky preaches peaceful reform in Nigeria.