At least 32 people were killed Tuesday when a bomb blast ripped through packed crowds in Yola, northeast Nigeria, just days after President Muhammadu Buhari visited declaring that Boko Haram were close to defeat.

The explosion happened at about 8:20 p.m. (7:20 p.m. GMT) in the Jambutu area of the Adamawa state capital, although it was not immediately clear whether it was caused by a suicide bomber or an improvised explosive device. "So far, we've recorded about 32 dead and about 80 injured," said Sa'ad Bello, the Yola coordinator for the National Emergency Management Agency.

The blast bore all the hallmarks of Boko Haram, which has previously attacked Yola with suicide bombers and improvised explosive devices in recent months. Buhari this month was in Yola to decorate soldiers for bravery in the counter-insurgency as well as visit a camp for people displaced by six years of violence that has left at least 17,000 people dead. He told troops he believed Boko Haram "are very close to defeat" and urged soldiers "to remain vigilant, alert and focused to prevent Boko Haram from sneaking into our communities to attack soft targets."

Red Cross official Aliyu Maikano and residents said the area targeted was a lorry park that also houses a livestock market, an open-air restaurant and a mosque. The area was immediately cordoned off but poor power supply in Yola meant the rescue effort was conducted in near darkness.

"Victims could be lying all over the place," Maikano said. Tuesday's blast was the first in Nigeria this month, indicating the army's strategy to cut off the extremists' supply lines and target their camps was paying off. Buhari has set his military commanders a deadline of the end of next month to crush the rebels, who have increasingly taken to attacking border areas of neighboring Chad, Niger and Cameroon. But the Yola explosion also shows the difficulty in completely neutralizing the threat, particularly in crowded urban areas.

On Monday, the army said it had foiled an attack using high-powered assault weapons and bombs in the capital of Borno state, Maiduguri, as well as having uncovered a bomb-making factory. Yola had been seen as a relative haven from the bloodshed across the northeast and last year housed hundreds of thousands who fled their homes as the militants advanced into Adawawa state. The military declared the state "cleared" earlier this year. But in October, 27 people were killed and 96 injured in a blast at a mosque in Jambutu, while in September, seven people died and 20 were injured by a bomb left at the displaced persons camp visited by Buhari last week.

Two suicide bombers blew themselves up at one of Yola's main markets in June, killing 31. There have also been multiple raids in the north of the state, near the group's Sambisa Forest stronghold across the border in Borno.

The blast came as Boko Haram was named in the latest Global Terrorism Index as "the most deadly terrorist group in the world," having killed 6,644 people last year. The index, published by the Institute for Economics and Peace, said DAESH, to which Boko Haram has pledged allegiance, killed 6,073. It highlighted "the major intensification of the terrorist threat in Nigeria" and said it had "witnessed the largest increase in terrorist deaths ever recorded by any country." Due to increasing militant group attacks, Nigeria also became the fourth deadliest country in the world, according to the 2014 figures released by a new think tank, Project for the Study of the 21st Century (PS21).

Meanwhile, Facebook has activated its "Safety Check" feature for the first time in Nigeria, after the bombing. "We've activated Safety Check again after the bombing in Nigeria this evening," co-founder and chief executive Mark Zuckerberg said in a post on the site.

The social network had come under criticism from those caught up in last Thursday's blasts in Beirut that they were not offered the service but those in Friday's Paris attacks were. The tool allows users to check whether friends are safe after attacks or natural disasters such as earthquakes. Zuckerberg said at the weekend the feature would be used more widely in the future.