Kano (Nigeria) (AFP) - A suicide bomber killed four people and wounded dozens Sunday in an attack on a bus station in Potiskum, northeastern Nigeria, police and hospital sources told AFP.
There was no immediate claim of responsibility, but the town has often come under attack from Boko Haram militants.
Last Sunday, two female suicide bombers, one believed to be aged around 15, carried out an attack on a crowded market.
Witnesses to the latest assault said the explosion ripped through the bus station at Tashar Kunne, on the outskirts of town, at around 10:30 am (0930 GMT).
"(The bomber) slowed his car twice... some distance from the bus station, and he suddenly increased speed and rammed into buses lined up waiting for passengers," local trader Umar Sani said.
A police officer said four bodies and 48 injured people had been taken from the scene.
A nurse at the Potiskum General Hospital gave a similar death and injury toll, and said local residents had rushed to the hospital in search of their loved ones.
She described the suicide bomber as a young man.
Potiskum has been hard hit previously in Boko Haram attacks. Fifteen people were killed in November 2014 during a Shiite religious procession. A week later a suicide bomber blew himself up in a high school, killing 58 people and wounding more than 100.
Brutal raids, massacres, suicide bomb attacks and kidnappings by Boko Haram have claimed at least 13,000 lives and driven an estimated 1.5 million people from their homes, mainly in arid northeast Nigeria.
Neighbouring Cameroon, Chad and Niger have launched a regional bid to combat the Islamists, as their attacks spread beyond Nigeria and concern mounts over the failure of Nigerian authorities to regain control.
On Saturday Chad sent troops, about 400 military vehicles including tanks and armoured vehicles, and several attack helicopters to Cameroon and Nigeria to aid in the fight against the Islamist militants.
A senior United Nations official on Friday called for a regional response to tackle Boko Haram.
"We have to come together to provide the support to the Nigerian government that has the primary responsibility to protect its people," Leila Zerrougui, the UN secretary-general's special representative on children and armed conflict, told AFP.
The military moves come after the Islamists seized the town of Baga on the shores of Lake Chad earlier this month in what many say could be Boko Haram's deadliest attack.
Satellite pictures released by Amnesty International and Human Rights Watch showed widespread destruction with around 3,700 buildings in Baga and nearby Doron Baga damaged or destroyed.
Amnesty says as many as 2,000 civilians may have been massacred, but Nigeria's army objected to the "sensational" claims and said the death toll in Baga was about 150.