Two attacks by suspected Islamic extremists in northern Nigeria have left at least 54 people dead, officials said Tuesday.
Security sources and witnesses who spoke to Reuters said the extremists were part of the Boko Haram terror group.
The group attacked a Nigerian military base and police barracks in a northeastern town Tuesday, killing at least 24 security personnel, the sources said.
The attack occurred near where Boko Haram shot or burned to death 59 students at a boarding school in February, the sources and witnesses told Reuters.
Meanwhile, traders in the market in Nigeria's central city of Jos, where two explosions on May 20 left more than 130 people dead, said police failed to act after traders warned them about an abandoned bus hours before the bombings.
"Our members reported to the police that they noticed the presence of the (Peugeot) J5 bus parked early morning on that fateful date, and we don't know the owner," said Kabiru Muhammad Idris, a member of the traders welfare committee at the Terminus market in Jos, the capital of Plateau state. "When the police came, they removed the plate number of the J5 Bus."
Idris, whose testimony was backed by other traders, said police didn't check the contents of the bus that later exploded.
Plateau state police spokeswoman Felicia Anslem denied the allegations.
"No one informed the police about the J5 bus that was allegedly parked," Anslem said, adding that traffic is high around the area so "there is no way a car could have been parked there from morning till evening." The explosion also took place in the center of the road, she said.
A second explosion followed the bomb from the bus on May 20, boosting the number of casualties as first respondents arrived.
This isn't the first time that security forces were accused of ignoring tips about imminent attacks or allegedly declining to take action to prevent them.
Amnesty International said the authorities failed to act, even though they were warned hours before Boko Haram militants kidnapped more than 300 schoolgirls from the remote town of Chibok in April.
Four days after the dual explosions, another attack was carried out in Jos, killing three people.
No one claimed responsibility for the attacks, though they carried the marks of Boko Haram, the Islamic extremist group that killed thousands since it began its violent campaign in 2009 to impose Islamic law on Nigeria.
The West African country is the most populous in Africa, with more than 170 million people almost evenly divided between a mainly Muslim north and a largely Christian south.
The Associated Press contributed to this report.