A bomb exploded at a bus station in northern Nigeria's Bauchi state late on Wednesday, killing at least five people and wounding 12, police said. The blast, which struck the town of Azare, is likely to be blamed on Islamist Boko Haram militants, casting further doubt on government reports that it had reached a temporary ceasefire with the rebels in order to secure the release of more than 200 schoolgirls they are holding hostage. Police did not comment on who was behind the attack. The insurgents have repeatedly bombed public places since they launched an uprising demanding an Islamic state in religiously mixed Nigeria five years ago. They have stepped up their campaign this year, setting off deadly blasts across the country. "Five persons burned beyond recognition were certified dead, while 12 others sustained various degrees of injuries," Bauchi police spokesman Haruna Mohammed said in a statement. "The entire surrounding (area) has been cordoned
off ... No arrest has yet been made, but an investigation has commenced." Nearly a week after the government announced a ceasefire deal with Boko Haram, which it said would include the release of the girls kidnapped from the secondary school in Chibok in northeastern Nigeria in April, there is still no sign of
them being freed. A number of attacks has raised doubts over the ceasefire, although Boko Haram is so factionalized it is possible a truce has been reached with one group, while others continue with violence. Talks to release the schoolgirls are taking place this week between the government and a Boko Haram representative in the Chadian capital N'Djamena, but they are shrouded in secrecy. A Chadian diplomat told Reuters that a deal could still be reached if this faction has ultimate control over the girls -- although analysts say that could be divided between several cooperating factions. Boko Haram, which only communicates messages via jihadist videos of a man claiming to be its leader Abubakar Shekau, has not yet commented on the alleged ceasefire.