Gunmen suspected to be members of the armed Boko Haram group have stormed the northeast Nigerian town of Gajiran, opening fire in a market and killing 15 people, the AFP news agency reported.
Borno state in the northeast, where the latest violence occurred, is a Boko Haram stronghold and has seen a spate of similar attacks on locals in recent weeks.
Residents of Gajiran, speaking to journalists in the state capital Maiduguri, said the gunmen involved in Thursday's attack pretended to be traders attending a local market.
"Some of them came aboard trucks while others came on foot to beat the security checks at the entrance of the town," resident Ibrahim Bulama said.
They then "blended among traders conducting business", before opening fire in the market, killing 15 people, he told reporters.
They also set fire to a local government building and a police post, he said.
Aisami Yusuf, another local speaking to journalists in Maiduguri, also put the death toll at 15 and provided a similar account.
Gajiran is roughly 85km from the state capital.
There has been no mobile phone service in Borno since the middle of May, when Nigeria declared a state of emergency across most of the northeast and launched an offensive aimed at crushing Boko Haram's fight against the state.
Details of attacks have been difficult to verify, with area police and military officers unreachable by phone.
The military has said it switched off the phones to block the group from coordinating attacks.
Last month, armed men dressed as soldiers opened fire on worshippers leaving a mosque in the far northeastern village of Dumba, killing at least 35 people.
Separately, on August 10 and 11, suspected Boko Haram members stormed a mosque in Konduga and shot dead 44 worshippers as well as 12 other people in a nearby village in another area of the northeast.
Boko Haram's campaign against the state has left more than 3,600 dead since 2009, including killings by the security forces, who have been accused of major abuses.
The group has claimed to be fighting for the creation of an Islamic state in Africa's most populous nation and largest oil producer, though it is believed to have a number of factions with varying aims.