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.
Analysis by Will Ross, BBC News, Abuja
The big question is where is Nigeria heading? The ferocity, frequency and geographical spread of the attacks is alarming. The military continues to fail to protect civilians in the north-east despite endless promises from the government that additional help is being sent there.
Boko Haram has in the past said it wanted to create an Islamic state. The current bombing campaign is indiscriminate, killing Christians and Muslims. Following most of the devastating attacks in the remote north-east this year, the government has been silent.
These days the president and government officials take less time to condemn, but there is no real sign that the military has the capacity to turn the tide against this brutal campaign of violence. That is terrifying.
The attack on Shawa happened on Monday and that on Alagarno on Tuesday, but were only reported on Wednesday.
Witnesses in Shawa said the gunmen had been on motorcycles. Villagers in Alagarno said the suspected Boko Haram fighters had arrived at night, forcing many residents to flee into the bush.
The militants left the village some four hours later with stolen food and vehicles. One survivor told the BBC that every building had been torched.
In Jos, the search for bodies has been continuing in the rubble left by the twin bombings.
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.
Nigeria's government has been accused of not doing enough to tackle the Islamist extremists - criticism that has grown since the abduction of the schoolgirls.
Earlier this month, the Nigerian senate unanimously approved a six-month extension of a state of emergency in Adamawa, Borno and Yobe states.
Boko Haram is fighting to overthrow the government and create an Islamic state. More than 1,000 people have been killed in attacks linked to the group this year alone.
Nigeria under attack
- 20 May: Twin bomb attacks killed at least 118 people in the central city of Jos
- 18 May: Suicide blast on a busy street in northern city of Kano kills four, including a 12-year-old girl
- 5 May: Boko Haram militants slaughter more than 300 residents in the town of Gamboru Ngala
- 2 May: Car bomb claims at least 19 lives in the Nigerian capital, Abuja
- 14 April: Twin bomb attack claimed by Boko Haram kills more than 70 at an Abuja bus station; the same day, the group abducts more than 200 schoolgirls from the remote northern town of Chibok