In Nigeria, a female suicide bomber has blown herself up at a teacher training college in central Niger State.
Police said the bombing took place around midday in the city of Kontagora. Authorities said the woman blew herself up en route to the school's library.
There were conflicting reports on whether anyone else died in the blast.
On Monday, at least 48 people, many of them students, were killed in a suicide bombing at a school in northeastern Nigeria. The blast occurred in the town of Potiskum, in the state of Yobe, as students gathered for a morning assembly at a government-run secondary school focused on science.
Medical workers say at least 79 people were injured in the blast, many of them seriously. Witnesses say the bomber was dressed like a student.
No one has claimed responsibility for either attack, but suspicion has fallen on militant group Boko Haram.
The group was blamed for an attack in Potiskum one week ago, when a suicide bomber attacked a religious procession, killing more than two dozen people.
Nigerian President Goodluck Jonathan condemned the attack and vowed to bring those responsible to justice. In a statement Monday he also extended his condolences to the families of the victims and the people of Yobe state.
U.N. Secretary-General Ban Ki-moon said he is outraged by the frequency and brutality of attacks against educational institutions in the north of Nigeria.
On Sunday, Boko Haram released a new video that shows group leader Abubakar Shekau giving a speech and armed militants parading and celebrating in an unidentified area.
Nigeria's military has said Shekau is dead but undated videos featuring the bearded militant continue to appear.
Boko Haram has killed thousands of people in the past five years in its campaign to establish what it calls an Islamic caliphate in northern Nigeria.
The group has carried out numerous attacks on schools, most notably in April, when it kidnapped 276 girls from a school in Borno state.
Boko Haram has increased its attacks since the government announced last month that it had reached a cease-fire agreement with the group. Reported talks between the government and militants in Chad later collapsed.
