Kano - Troops have killed Boko Haram spokesman Abu Qaqa, in a gun battle in the northern city of Kano, a senior security source said on Monday.
The source, who spoke on condition of anonymity, said the man killed on Sunday had been identified as "Anwal Kontagora, alias 'Abu Qaqa'", whose pen name often appears in the sect's pronouncements from its northeastern base.
Boko Haram has killed hundreds of people since 2009 in attacks on security forces, government offices and churches, and has been designated a terrorist group by the United States. At least 186 people died in coordinated attacks in Kano in January.
The group, which models itself loosely on the Afghan Taliban, wants to carve out an Islamic state in northern Nigeria, but a military crackdown appears to have weakened its capabilities, and it has not managed a large-scale deadly strike for several months.
The source said troops had also killed Isah Abuja, a deputy seen as a likely replacement for sect leader Abubakar Shekau in the event of his death or capture.
"We had been trailing them since 2 a.m. along the Kano-Maiduguri road," the source said, adding that because of the curfew, the suspects had stopped at a roadblock on the outskirts of Kano in an area called Hotoro, when the gun fight erupted.
There was no immediate comment from Boko Haram.
A spokesman for the military and police joint task force in Kano, Lieutenant Ikedichi Iweha, had slightly different information: "One person was killed in a gun battle while two others were captured alive but, as for their identities, for now we don't know."
A man calling himself Abu Qaqa often appears in local media or speaks to journalists by telephone to claim responsibility for gun or bomb attacks for the group, justify its actions, deny involvement in incidents, or threaten the media.
For a long time, Abu Qaqa was the closest thing the sect had to a public figure, before its purported leader Abubakar Shekau began posting videos of himself on YouTube in January.
Nigerian authorities in March claimed to have arrested Abu Qaqa, only to have him appear publicly to deny it. The man they had caught turned out to be another of the sect's members.
The name is thought to be a pseudonym, complicating efforts to verify his identity, Nigerian security sources say.
"You might say the man killed is Qaqa, then next moment you hear another Qaqa on air. So we are being careful," said Iweha.
About a week ago, Boko Haram started attacking mobile phone installations, saying phone companies were helping authorities to track its fighters down.
On Sunday, suspected Islamists on motorcycles shot dead an off-duty military officer, his wife and their disabled child, police said.