But witness says stray bullets hit innocent civilians during clash between soldiers and Islamist insurgents in city of Maiduguri
Nineteen people were killed during clashes with Islamist insurgents in north-eastern Nigeria on Tuesday, officials said.
The violence, which authorities blamed on the radical Boko Haram sect, hit the cities of Kano and Maiduguri, where the group once had its main mosque.
The heaviest fighting was in Maiduguri, where soldiers fired on suspected sect members for several hours and bomb blasts echoed across the city, witnesses said.
An army spokesman, Colonel Victor Ebhaleme, said on Tuesday night that all 16 of those killed were "Boko Haram terrorists" and that the military suffered no casualties.
Soldiers also recovered weapons and ammunition in the operation, which targeted areas authorities believed served as hideouts for the sect in the city, Ebhaleme said.
However, a man who lives in the neighbourhood where the fighting took place said some civilians had been struck by stray bullets in the fighting.
"I almost got home, but I saw soldiers shooting and I had to run back," the man said. He spoke on condition of anonymity as he feared angering either the military or Boko Haram.
The crowded neighbourhood, called Lawan Bukar, is close to the palace of the region's traditional ruler, the Shehu of Borno.
It was also the site of a recent attack by suspected Boko Haram members in which two civilians were beheaded and a politician shot dead.
In Kano, Boko Haram suspects shot and killed a retired senior federal policeman and two other officers.
Nigeria faces a growing wave of sectarian violence carried out by Boko Haram. The sect's name translates as "Western education is sacrilege" in the Hausa language of Nigeria's predominantly Muslim north.
The sect has been blamed for killing more than 560 people this year alone, according to the Associated Press. Targets have included churches, often attacked by suicide car bombers.
Boko Haram, which speaks to journalists through telephone conference calls at times of its choosing, could not be reached for comment on Tuesday.
The sect most recently claimed responsibility for a suicide car bombing at a church in the northern state of Bauchi on Sunday. That attack killed at least 15 people and wounded dozens more.
Nigeria, a nation of 160 million people, is divided between the largely Muslim north and the Christian south.
Boko Haram attacks have inflamed tensions between the two religions, though many in the two faiths live peacefully with each other and intermarry.