MAIDUGURI - Fighters from Nigerian Islamist militant group Boko Haram stormed the northeastern town of Mainok on Friday, sparking a gun battle that killed at least 36 people and continued into Saturday, two security sources said.

Four civilians were also killed in the remote north of Cameroon in a cross-border attack by Boko Haram militants, according to Cameroon state radio. Boko Haram has killed thousands over the past five years in its struggle for an Islamic state in northeast Nigeria. ‘Thirteen of the terrorists who came to attack civilians in Mainok market yesterday were killed, some of them fled with gunshots and our colleagues are already on their trail. Unfortunately, 23 civilians died in the attack,’ one of the sources said. The other said the death toll may be even higher, saying he had counted 25 bodies on one road. The Nigerian military did not immediately respond to a request for comment. Since a military offensive began last year the Islamists have taken out their anger on civilians in increasingly frequent attacks. They have also branched out to strike in areas far from the rebel strongholds.

Gunmen stormed a higher education college in northern Nigeria’s main city of Kano on Wednesday, firing on fleeing students and triggering an explosion in an attack that killed at least 15 people and wounded 35, police said. Boko Haram rebels have also made several incursions into the hilly jungle region of neighbouring Cameroon in recent months. Cameroon has deployed troops to the border in an attempt to repel them.

Cameroon’s army responded after an assault on the village of Assighassia near the city of Mokolo, and two militants were killed and a Cameroonian soldier injured, state-run Cameroon Radio Television reported late on Friday.

‘Two hours later, the terrorist group again attacked the village of Ganse, also close to Mokolo, and killed four civilians.’ Officials in the Cameroon defence ministry said on Saturday they had been informed of the clashes and were seeking to confirm the details.

More than 40,000 people have fled to Cameroon to escape Boko Haram attacks in northern Nigeria, according to the UN refugee agency UNHCR, leaving behind few but the elderly and the disabled in their villages across the border. But once over the border they are still not safe and UNHCR is seeking to transfer many of them to a refugee camp further from the frontier at Minawao. Foncha Ngeh, a businessman based in Cameroon’s northern hub of Maroua, said that hundreds of people were fleeing from isolated border villages in Cameroon to bigger towns and cities in search of safety. Boko Haram have killed hundreds of people this year, mostly in northeastern Nigeria, although they have launched attacks across the country. Moreover, Boko Haram gunmen stormed a crowded market in Nigeria’s restive northeastern state of Borno, killing several people and carting away food, witnesses said Saturday.

Dressed in military and police uniforms, dozens of insurgents attacked the town of Mainok, 56 kilometres outside Maiduguri, the state capital late Thursday, firing a rocket-propelled grenade and spraying the market with bullets. The attackers also looted food which they loaded onto trucks abandoned by fleeing traders, witnesses said.

‘They struck around 1:30pm during peak hours by first firing a rocket-propelled grenade at the market before opening fire on traders’, Salman Lawan, a trader who witnessed the carnage told AFP. ‘They killed several people in the attack but it is difficult to give a precise figure,’ said Lawan who fled to Maiduguri following the attack.

Another trader Modu Kachalla, who gave a similar account, said the insurgents were looking for cash and food. ‘They robbed traders of cash and loaded food into trucks they seized at the market before fleeing into the bush,’ he said. ‘The market was full when the Boko Haram gunmen attacked which explained the high casualties,’ he said. ‘The attackers killed many people at the market but it is difficult to give a toll because everybody fled to save their lives,’ said Ibrahim Kolo, another witness.

Boko Haram, which has seized swathes of territory in Borno and in neighbouring Yobe and Adamawa states, has been running short of food in the areas they have taken, according to residents. On Wednesday the insurgents ambushed a truck carrying grain to Maiduguri outside the nearby village of Ngamdu and looted it before setting it on fire, they said. The news of the attack on the market was slow to emerge due to disruption in phone services in the region on Friday. Telecoms services were only restored on Saturday.

Mainok has suffered repeated attacks by Boko Haram, which wants to impose a hardline Islamic state in the mainly Muslim north. In February scores were killed there and many homes destroyed by the extremists. Their insurgency has claimed more than 10,000 lives since 2009 and left more than 700,000 homeless. The Nigerian military has come under increasing pressure as the Islamists have captured more territory in the volatile northeast in recent weeks.