A bomb blast and gunfire shook an area around an Islamic boarding school in northern Nigeria on Sunday, leaving two of the alleged attackers dead and others wounded, emergency officials said.

It was not immediately clear who was behind the blast in the city of Zaria, but Islamist extremist group Boko Haram has been blamed for hundreds of deaths as part of its insurgency in northern and central Nigeria.

Nigeria's military said Friday it had arrested a number of security personnel over links to Islamist extremist group Boko Haram, whose insurgency has killed hundreds of people.

The arrests came after soldiers from a special military unit deployed in the northeastern city of Maiduguri arrested an immigration officer, Grema Mohammed, for allegedly being an active member of Boko Haram, a military spokesman said.

A Qatar airways flight from Doha safely made an emergency landing in the Nigerian economic capital Lagos on Saturday after encountering a problem with its tires, the civil aviation body said.

"The plane has landed safely," said Harold Demuren, the head of Nigeria's Civil Aviation Authority. "We lost one of the tires... We are now towing the aircraft," at Murtala Mohammed International airport, he added.

U.N. chief Ban Ki-moon Wednesday urged world leaders "not to abandon" the Sahel region, but urged caution amid calls for military intervention to flush out armed Islamist rebels in northern Mali.

"The region needs your attention, your focus. Do not abandon it and regret it later," Ban told a high-level meeting on the sidelines of the U.N. General Assembly.

Nigeria's military said Tuesday that it has killed a senior Boko Haram Islamist leader and arrested 156 suspected members of the group during a weekend raid in northeastern Adamawa state.

"In the three-day operation, the town was placed under 24-hour curfew, which enabled soldiers to comb the nooks and corners," said Lieutenant Saleh Mohammed Buba, military spokesman in Adamawa.

A suicide bomber who tried to ram an explosives-packed car into a church in Nigeria on Sunday killed a woman and a child while badly wounding dozens more, the Red Cross said.

The attacker targeted the St. John's Catholic Church in the northern city of Bauchi, where tight security was imposed after a wave church bombings claimed by the radical Islamist group Boko Haram.

Tens of thousands of people on Saturday protested on the streets of Nigeria's second city of Kano against an anti-Islam film made in the U.S. that has stirred outrage across the Muslim world.

An AFP reporter said the crowd of demonstrators stretched several kilometers through the city, the largest in Nigeria's mainly Muslim north, with protesters shouting "death to America, death to Israel and death to the enemies of Islam".

Thousands of Muslims marched in the Nigerian city of Zaria and burnt U.S. and Israeli flags on Thursday to protest a U.S.-made anti-Islam movie that has drawn demonstrations in various countries.

The protesters under the auspices of the pro-Iranian Shiite group Islamic Movement of Nigeria carried banners and placards denouncing the United States and Israel while calling for the prosecution of the film producers.

Gunmen have killed the justice commissioner for a Nigerian state at the heart of an Islamist insurgency and an ex-prisons chief in another area, government and police sources said Tuesday.

It was not immediately clear who was behind the killings, but they occurred after security forces on Monday shot dead two suspected high-ranking members of Islamist extremist group Boko Haram.

Nigerian soldiers on Monday shot dead a man suspected to have acted as a spokesman for Islamist group Boko Haram and arrested two other high-ranking members, a military official said.

"We carried out an operation early this morning in which we killed a media man of Boko Haram terrorists and arrested two field commanders of the sect," said Lieutenant Iweha Ikedichi, spokesman for a military task force, adding he did not have their exact identities.