A mob in the northeast Nigerian city of Bauchi on Sunday beat a woman to death and burnt her body over suspicion she was a suicide bomber, police and witnesses said.

"At about 0700 hours (0600 GMT), information at our disposal revealed that a yet to be identified lady who allegedly refused to allow herself to be screened at the entrance of Muda Lawal Market Bauchi was attacked by irate mob," Bauchi state police spokesman Haruna Mohammed said in a statement.

Bomb attacks in Nigerian towns and cities look likely to increase in the run-up to forthcoming elections, despite the military claiming increasing successes against Boko Haram in captured territory.

At least 86 people were killed in explosions blamed on Boko Haram this week alone, all of them at crowded bus stations in the northeast, wider north and also in the country's central region.

Boko Haram fighters have raided villages in northeast Nigeria on the border with Cameroon, apparently in reprisal for a Chadian offensive against its hideouts, residents told Agence France-Presse on Friday.

Scores of heavily armed militants on Wednesday rampaged through more than a dozen villages in the Kala-Balge district in Borno state, shooting, hacking residents to death and razing homes.

The U.S. Treasury Department has said that it placed sanctions on an Africa-based Hizbullah support network.

Mustapha Fawaz, Fouzi Fawaz, and Abdallah Tahini were sanctioned for acting for or on behalf of Hizbullah in Nigeria, the Treasury said in a statement.

Nigeria's President Goodluck Jonathan on Thursday visited the scene of what is feared to be Boko Haram's worst massacre and vowed that the insurgency would soon be over.

But the Islamists gave a fresh indication of the scale of the task, with three separate bombings in the country's religiously tense central region and restive northeast that left at least 35 people dead.

A twin suicide attack this week at a bus station in Nigeria's Kano city killed 34 people, a union official said Thursday, giving an updated toll after police said 10 people died.

Boko Haram Islamist militants have not claimed the blasts, but the group has repeatedly targeted Kano, including bus stations, throughout its six-year uprising.

The head of the Nigerian Army has visited soldiers in the northeastern town of Baga, telling troops that the conflict against Boko Haram will soon be over.

Lieutenant General Kenneth Minimah flew by helicopter to the fishing hub on the shores of Lake Chad and spent about 30 minutes on the ground, an AFP correspondent accompanying him said.

Nigeria's President Goodluck Jonathan on Tuesday said the military was gaining the upper hand against Boko Haram, despite two bombings in the country's north that killed at least 27.

"The President assures all Nigerians, and the people of the northeastern states in particular, that the days of mourning victims of incessant terrorist attacks in the country will soon be over as the tide has now definitely turned against Boko Haram," his office said in an emailed statement.

Masked gunmen in central Nigeria kidnapped an American woman doing missionary work, with ransom the suspected motive for the attack, police told AFP Tuesday.

"She was whisked away at around 10:00 am (0900 GMT) Monday," said Kogi state police spokesman Sola Collins Adebayo.

Long before Boko Haram's uprising plunged the region into crisis, the area below Lake Chad was part of a powerful Islamic empire, known for religious piety and unity spanning roughly 1,000 years.

The scope of the Kanem-Bornu empire changed repeatedly from its founding in the ninth century to its downfall in the 1890s but at its height the kingdom included modern day northeast Nigeria, as well as parts of neighboring Cameroon, Chad and Niger.