Gunmen believed to be from Islamist extremist group Boko Haram have opened fire at a market in volatile northeastern Nigeria, killing 18 people, a local official said on Tuesday.
"Some gunmen came into the market yesterday afternoon and opened fire on a group of hunters," local chief Abba Ahmed told journalists of the attack in Damboa.
"Eighteen people were killed in the attack."
There were conflicting reasons given for the attack. According to Ahmed, there were claims that the Islamists were angry over the hunters selling meat such as pork forbidden in Islam.
Other residents however spoke of hunters in the area recently banding together to form a local vigilante group in response to robberies by Boko Haram members, sparking a revenge attack from the Islamists.
Hunters typically sell their game at the market in Damboa where the attack occurred.
Violence linked to Boko Haram's insurgency in northern and central Nigeria has left some 3,000 people dead since 2009, including killings by the security forces.
Damboa is located near the city of Maiduguri, the heart of the insurgency and where Boko Haram has been based.
There has been a lull in major attacks in recent weeks in Nigeria, but there were two high-profile attacks at the weekend.
On Saturday, an explosion in central Nigeria killed two soldiers who were due to be deployed to Mali. A group calling itself Ansaru, thought to be a Boko Haram splinter group, claimed responsibility.
Nigeria is set to deploy some 900 troops to Mali to contribute to an African force aimed at helping the country battle Islamists who seized control of its north in April last year. It will command the force as well.
Also on Saturday, gunmen opened fire on the convoy of the emir of Kano, an influential Nigerian Muslim figure, killing five people. The 82-year-old emir Ado Bayero was not hurt, but two of his sons were wounded.
No one has claimed responsibility for that attack, which sparked outrage in Nigeria, Africa's most populous nation and largest oil producer, roughly divided between a mainly Muslim north and predominately Christian south.
Boko Haram has claimed to be fighting for the creation of an Islamic state, but its demands have repeatedly shifted and it is believed to include various factions. Criminal gangs and imitators are also suspected of carrying out violence under the guise of the group.
Its attacks have included assassinations and suicide bombings, including one at UN headquarters in the capital Abuja in August 2011 which killed at least 25 people.
While Muslims and symbols of Nigerian authority have often been its victims, it has also targeted Christians, including through the use of church bombings.