Security officers stand guard at the scene of an explosion at a mobile phone market in Kano, Nigeria. Wednesday. (Muhammed Giginyu/AP)

At least 34 people were killed and 80 wounded in a suicide bombing at a bustling marketplace in Yola, a town packed with refugees from Nigeria’s Islamist uprising, emergency officials said Wednesday.

Later Wednesday, two more suicide bombers killed at least 15 people in the northern Ni­ger­ian city of Kano and injured 53, according to police. But Nigeria’s National Emergency Management Agency said more than 100 were injured in the Kano explosions.

The blasts were thought to be the latest by Boko Haram, Nigeria’s homegrown Islamist extremist group, whose six-year-old insurgency has killed an estimated 20,000 people and forced about 2.3 million to flee their homes.

Boko Haram was named Wednesday as the world’s deadliest extremist group in the Global Terrorism Index. Deaths attributed to Boko Haram increased by 317 percent in 2014 to 6,644, compared with 6,073 blamed on the Islamic State group. Boko Haram pledged allegiance to the Islamic State in March.

Wednesday’s explosions came as President Muhammadu Buhari pressed his campaign against Nigeria’s endemic corruption, which is seen as hampering the fight against the insurgents. Buhari accused his predecessor’s national security adviser, Sambo Dasuki, of stealing billions of dollars meant to buy weapons to fight Boko Haram, when soldiers were short on ammunition for their rifles and the extremists were rampaging across northeast Nigeria.

Critics have long blamed corruption for the military’s failures, asking how the insurgents can be better armed than Nigerian soldiers despite the government’s annual defense budget of more than $5 billion, supplemented last year by a loan of $1 billion.

In addition to Dasuki, Buhari ordered the arrests of several former senior officials allegedly linked to fraudulent and fictitious arms contracts totaling $5.4 billion, one of the president’s advisers, Femi Adesina, said in a statement.

Dasuki is accused of awarding “phantom contracts” to buy 12 helicopters, four fighter jets and munitions worth $2.9 billion that never were supplied, Adesina said. Buhari fired him in July.

In a statement, Dasuki said that the allegations were “laughable” and that “I am not a thief or treasury looter as being portrayed.”

The unending violence has torn apart Nigeria’s northeast. In Yola, hit by a suicide bombing for the third time in as many months, relatives searching for missing loved ones converged on the two main hospitals.

“I couldn’t find them at the hospital, so I had to come to the mortuary,” a distraught Musa Adamu said. He said that his brother, Kamal, was selling sugar cane to truckers and that his uncle had gone to look for him.

Adamu found the bodies of both men in the morgue.