The insurgents were said to have taken control of Malam Fatori in Nigeria's northeastern Borno state after fighting on Wednesday and Thursday, a senior official in the Niger town of Diffa near Nigeria told AFP on condition of anonymity.
The fighting killed dozens and wounded about 30 people in the a commercial hub known for fishing and farming, the Anfani radio station in Diffa reported.
"The town of Malam Fatori was taken by Boko Haram after violent fighting with the Nigerian army overnight Wednesday to Thursday," said the official in Diffa, where thousands of refugees from the conflict have fled to.
The official's version of events differed from the one given by a Nigerian senator, who on Thursday spoke of the attack but did not say that the town had been taken.
Senator Maina Maaji Lawan said the insurgents met stiff resistance from soldiers from a multi-national task force in the region that includes troops from Nigeria, Chad and Niger.
Lawan however also said that soldiers were later forced to flee after being overpowered by the insurgents. He said that 21 civilians were killed.
It has occasionally carried out cross-border attacks, and another such raid occurred on Saturday in Cameroon.
In that attack, Boko Haram members attacked a Cameroon border town, leading to six hours of fighting that killed a soldier and several insurgents, authorities said.
The attack occurred in Kerawa, near areas of Nigeria recently taken over by Boko Haram. The nearby Mandara mountains have been used as a hideout by Boko Haram members.
