Iranian officials have condemned the Nigerian army's crackdown on a Shi'ite religious sect that reportedly left hundreds dead in the country's north. Iran's parliament on Tuesday called on the Nigerian president to launch an investigation into the deaths, while the foreign ministry summoned the top Nigerian diplomat to protest the killings. Activists and sect leaders say up to 1,000 Shi'ite Muslims were killed during weekend raids in the northern city of Zaria, in Kaduna State. The Nigerian army confirms there were clashes in Zaria but has not released a death toll. The violence began Saturday after members of the Islamic Movement of Nigeria (IMN) blocked a highway and according to witnesses stoned the convoy of Nigerian army chief General Tukur Buratai. An army spokesman called the stoning an "attempt to assassinate" the general. The Shi'ite group says there was no assassination attempt and that the army had launched a pre-planned attack on the group. It says troops launched attacks and killed people "indiscriminately" at three locations, including the home of the group's leader, Ibraheem Zakzaky. One of Zakzaky's wives was reportedly killed along with a son. Nigeria's Vanguard newspaper quotes an army official saying that Zakzaky is in their custody. The Islamic Movement of Nigeria seeks to establish an Islamic state in northern Nigeria through an Iranian-style revolution. The group is not connected to Boko Haram, the Islamist radical sect blamed for more than 10,000 deaths in Nigeria during the past six years.