A blast in northeastern Nigeria's Borno State has killed at least 47 people and injured another 52, according to a military source and a civilian joint task force member.
The explosion, in a region where hundreds of people have been killed in attacks by suspected members of Boko Haram in the last few weeks, struck the town of Sabon Gari at around 1:30pm local time on Tuesday, the sources said.
Al Jazeera's Ahmed Idris, reporting from the city of Kano, said the attack happened close to a cattle market.
"According to sources in the area, this attack was carried out by a female suicide bomber who detonated her device," he said.
He said security is very tight in the area at the moment as an operation by the Multi-National Task Force, a coalition of African countries fighting Boko Haram, is ongoing.
"We have received at least 47 dead bodies and at least 50 with injuries from the Sabon Gari market, where there was a blast this afternoon," a nurse at Biu General Hospital, around 50km away, told AFP news agency.
The nurse said the injuries from the blast are mostly "severe" and that the death toll was expected to rise.
"The explosion happened inside the market at the mobile phone section, near the livestock section of the market," said Yuram Bura, a member of a local vigilante group fighting Boko Haram alongside the army.
"It was concealed in a napsack used for spraying herbicides. It was smuggled into the market and apparently abandoned. This is no doubt the handiwork of Boko Haram."
In neighbouring Cameroon, troops repelled an attack on Ashigashia, killing 10 and forcing the fighters to retreat, according to military spokesman Colonel Jaco Kodji.
Two soldiers were wounded but no civilians were reported injured, he said.
A regional army of 8,750 troops from five nations was supposed to be deployed in November but has been delayed.
Nigeria's President Muhammadu Buhari, who was inaugurated at the end of May, had pledged the force would be active by the end of July.
Delays have been blamed on funding and uneasy relations between Nigeria and its neighbours.
The US "strongly condemns" the attack on the market and believes "the people of northern Nigeria deserve to live free from violence and from terror", John Kirby, state department spokesperson, said in a statement.
Kirby said the US would continue to provide a range of counterterrorism assistance to help Nigeria and its regional partners fight against Boko Haram.
Source: Al Jazeera and agencies