A suicide bombing at a Shiite ceremony killed at least 15 people in northeastern Nigeria on Monday while 132 inmates were at large after a daring prison break.
The attack in Potiskum, the commercial capital of Yobe state, came as Shia Muslims marked Ashura, the anniversary of the death of Hussein, the grandson of the Prophet Mohammed.
The prison break saw armed gunmen use dynamite to blast open the detention facility in central Kogi state late on Sunday, more than two years after Boko Haram launched an attack at the same facility.
Meanwhile in Adamawa state, also northeast Nigeria, tens of thousands of people fled their homes to refugee camps after the militants seized control of the commercial hub of Mubi.
The three incidents underscored fragile security in Nigeria and again looked likely to dent government claims of a ceasefire deal and peace talks to end five years of deadly Boko Haram violence.
The group's leader, Abubakar Shekau, on Friday dismissed the government's assertion of talks and an end to hostilities as "a lie".
He also claimed that the 219 schoolgirls kidnapped in mid-April, whose plight caught world attention, had all converted to Islam and been "married off".
- Ashura attack -
In Potiskum, police and eye-witnesses said a bomb went off 10 metres (32 feet) from a seminary where Shia worshippers had gathered for the Ashura festival after visiting the local emir's palace.
"We lost 15 of our members in a suicide blast at the end of our Ashura procession," the head of the city's Shiite community, Mustapha Lawan Nasidi, told AFP.
Fifty people were also injured, he said, adding that several others died when troops who deployed to the scene opened fire. There was no immediate response from the military.
Potiskum is the economic capital of Yobe, which with Borno and Adamawa states have been under emergency rule since May of last year because of the insurgency.
The area has seen repeated violence, including attacks on the minority Shiite community.
In July, four Shiites were killed in a bomb attack blamed on the Sunni Islamists of Boko Haram at an open-air mosque in the Dogo Tebo area of the city.
- Prison break -
In Kogi, national police spokesman Emmanuel Ojukwu said unidentified gunmen blew up the prison with explosives late on Sunday, allowing scores to escape.
Jacob Edi, spokesman for Kogi's Governor Idris Wada, added: "There were 145 prisoners at the time of the attack.
"One died, eight have been recaptured and four surrendered voluntarily. The rest are at large."
Kogi is far south of Boko Haram's main area of operations but the Islamists claimed a prison raid at the same facility in 2012 that freed more than 100 inmates.
Many of the group's fighters were thought to have been held at the targeted Koton Karfi prison.
Ojukwu said the raid was not linked to the five-year Islamist uprising, blaming it instead on "criminal activity."
Nevertheless, Boko Haram have previously made a prisoner swap a condition for the release of schoolgirls, who were seized from the town of Chibok in Borno state on April 14.
Other prison breaks such as the March 14 raid on a military detention facility in the Borno state capital, Maiduguri, have been linked to Boko Haram's need to replenish its ranks.
- Mubi overrun -
In Adamawa, the National Emergency Management Agency (NEMA) said they had recorded at least 10,496 internally displaced people in five camps in the state capital, Yola, after violence in Mubi.
Thousands of residents from Mubi, which is Adamawa's second-largest town, have fled in the past week after Boko Haram's take-over of the town last Wednesday.
Mubi, which is 200 kilometres (120 miles) from Yola with a population of 150,000 is the commercial hub of Adamawa state and has been repeatedly attacked by Boko Haram.
The town has seen an influx of thousands of residents from nearby towns and villages seized by Boko Haram in the past two months. Hundreds of residents were still reportedly trapped in Mubi.
Nigerian soldiers reportedly fled to the town of Hong, 100 kilometres from Yola, according to residents who saw them en route.
In Mubi itself, resident Saleh Abdullahi said Boko Haram "came with their women and children and are now in firm control".
"They move about in vehicles and on foot patrolling the streets and keep telling people we are now under the authority of an Islamic state," Abdullahi said.