World

Boko Haram attacks biggest city in northeastern Nigeria, dozens of fighters killed, wounded

  • A near deserted street is photographed as a curfew is placed on people after clashes between Nigerian troops and Islamic extremists, in the city of  Maiduguri, Nigeria,  Sunday, Jan. 25, 2015, In fierce fighting Sunday, Nigerian troops clashed with Islamic extremists who attacked Maiduguri, the biggest city in northeast Nigeria. Dozens of combatants have been killed and wounded, soldiers and hospital workers said.  (AP Photo/Jossy Ola)

    A near deserted street is photographed as a curfew is placed on people after clashes between Nigerian troops and Islamic extremists, in the city of Maiduguri, Nigeria, Sunday, Jan. 25, 2015, In fierce fighting Sunday, Nigerian troops clashed with Islamic extremists who attacked Maiduguri, the biggest city in northeast Nigeria. Dozens of combatants have been killed and wounded, soldiers and hospital workers said. (AP Photo/Jossy Ola)  (The Associated Press)

  • U.S. Ambassador to Nigeria James Entwistle, left, US Secretary of State John Kerry, centre,  sit beside Nigeria's President Goodluck Jonathan, at the State House, in Lagos, Nigeria, Sunday,  Jan. 25, 2015. U.S. Secretary of State John Kerry's plan to stop in Nigeria for meetings with the two leading candidates in the upcoming presidential election signals deep U.S. concerns about pos telection violence in a country already devastated by an al-Qaida-linked insurgency. (AP Photo/Akintunde Akinleye, Pool)

    U.S. Ambassador to Nigeria James Entwistle, left, US Secretary of State John Kerry, centre, sit beside Nigeria's President Goodluck Jonathan, at the State House, in Lagos, Nigeria, Sunday, Jan. 25, 2015. U.S. Secretary of State John Kerry's plan to stop in Nigeria for meetings with the two leading candidates in the upcoming presidential election signals deep U.S. concerns about pos telection violence in a country already devastated by an al-Qaida-linked insurgency. (AP Photo/Akintunde Akinleye, Pool)  (The Associated Press)

  • U.S. Ambassador to Nigeria James Entwistle, centre left walks with US Secretary of State John Kerry, centre and unidentified Nigerian government officials upon Kerry's arrival, in Lagos, Nigeria, Sunday,  Jan. 25, 2015. U.S. Secretary of State John Kerry's plan to stop in Nigeria for meetings with the two leading candidates in the upcoming presidential election signals deep U.S. concerns about pos telection violence in a country already devastated by an al-Qaida-linked insurgency. (AP Photo/Akintunde Akinleye, Pool)

    U.S. Ambassador to Nigeria James Entwistle, centre left walks with US Secretary of State John Kerry, centre and unidentified Nigerian government officials upon Kerry's arrival, in Lagos, Nigeria, Sunday, Jan. 25, 2015. U.S. Secretary of State John Kerry's plan to stop in Nigeria for meetings with the two leading candidates in the upcoming presidential election signals deep U.S. concerns about pos telection violence in a country already devastated by an al-Qaida-linked insurgency. (AP Photo/Akintunde Akinleye, Pool)  (The Associated Press)

Nigeria's military says Islamic extremists are attacking Maiduguri, the biggest city in northeast Nigeria, and a soldier says dozens of combatants have been killed and wounded.

Troops are blocking roads leading to Maiduguri, a city of more than 1 million, preventing civilians from escaping.

Amnesty International says hundreds of thousands of civilians "are now at grave risk."

An officer involved in the fighting, who insisted on anonymity because he is not authorized to speak to the press, said the extremists attacked on three fronts around Maiduguri early Sunday and dozens of fighters have been killed.

Military spokesman Chris Olukolade tweeted that "coordinated air and land operations are being conducted now."

Maiduguri has been attacked many times in Nigeria's five-year Islamic insurgency that killed 10,000 people last year.