The Islamist group Boko Haram has been accused of killing at least 27 people in attacks on two villages in north-east Nigeria, close to where hundreds of schoolgirls were seized.
Gunmen killed 10 people in the village of Shawa and a further 17 in Alagarno, police and witnesses said.
The area is near Chibok, where the schoolgirls were abducted last month.
On Tuesday 118 people died in a double bombing in the central city of Jos, also blamed on Boko Haram.
The abductions of more than 200 girls caused international outrage and prompted foreign powers, including the US, to send military advisers to assist Nigeria’s army.
In another development on Wednesday, US President Barack Obama said 80 military personnel had been deployed to neighbouring Chad to help search for the missing girls.
“These personnel will support the operation of intelligence, surveillance and reconnaissance aircraft for missions over northern Nigeria and the surrounding area,” Mr Obama said in a letter to Congress.
Many parts of restive north-east Nigeria are no-go zones for the military and insurgents operate freely there, correspondents say.
The attacks targeted a crowded market and a hospital, and the second blast went off 30 minutes after the first – killing rescue workers who had rushed to the scene.
“People were using wheelbarrows to move bodies and limbs,” eyewitness Janzen Weyi told the BBC.
There has been widespread international condemnation.
US state department spokeswoman Jen Psaki said the bombing, and other recent attacks blamed on Boko Haram, were “unconscionable, terrorist acts”.
UK Foreign Secretary William Hague called the attack in Jos a “cowardly, inhumane crime”.
Nigeria’s President Goodluck Jonathan said those who carried out the attacks were “cruel and evil”.
The president announced increased measures to tackle the militants, including a multinational force around Lake Chad which comprises a battalion each from Chad, Niger, Cameroon and Nigeria.