Suspected Islamist militants from the Boko Haram group have killed at least 35 people in north-eastern Nigeria, local officials have said.They say the gunmen raided the village of Demba in Borno state after locals refused to co-operate with them.The attack happened on Monday, but details emerged only now because of the remoteness of the area.Boko Haram, which has waged a deadly insurgency in Nigeria since 2009, has so far not commented on the incident.'Throats slit'The attack on the village, near the town of Baga, took place on Monday, the officials said.Defence spokesman Brig Gen Chris Olukolade said that 14 people had been injured in the raid, according to the AFP news agency.An emergency worker told Reuters news agency: "They set houses ablaze, shot people and even slit some people's throats."The attack happened on the same day as the Nigerian military announced that Boko Haram leader Aubabkar Shekau may have been killed by security forces during a shoot-out in north-eastern Nigeria.An "intelligence report" showed that Shekau may have died between 25 July and 3 August, army spokesman Lt-Col Sagir Musa said.There is no independent confirmation of Shekau's death.A claim in 2009 that Shekau had been killed turned out to be untrue, they add.He became leader of Boko Haram after its founder, Muhammad Yusuf, died in police custody in the same year.The insurgency became far more brutal under Shekau's leadership, with Boko Haram carrying out a wave of bombings and abductions, including that of foreigners, in its campaign to create an Islamic state across Nigeria.In May, President Goodluck Jonathan declared an emergency in three north-eastern states, saying the group threatened Nigeria's existence.