Nigeria says it has launched a "massive deployment of men and resources against Islamist insurgents, a day after the country's president declared a state of emergency in three northeastern states.
The Nigerian military said in a statement Wednesday it is aiming to rid the nation's border territories of terrorist bases."
Major attacks blamed on Nigeria's Boko Haram
July - Attacks prompt government crackdown in Bauchi and Maiduguri; 800 people killed
December - Bombings in central Nigeria and church attacks in the northeast kill 86
June - Attack on a bar in Maiduguri kills 25
August - Suicide bomber kills 23 at U.N. building in Abuja
November - Bombings in Damaturu and Potiskum kill 65
December - Christmas Day bombings across Nigeria kill 39
January -- Gun and bomb attacks in Kano up to 200
February - Maiduguri market attack kills 30
June - Suicide car bombings at three churches kill 21
July - Attacks in Plateau state kill dozens, including two politicians at a funeral for the victims
February - French family kidnapped in Cameroon, held hostage for two months
April - Fighting with troops in Baga kills up to 200; residents say troops set deadly fires
May - Attacks in Bama kill more than 50
July - Gunmen kill 30 at a school in Yobe
August - Gunmen kill 44 at a mosque outside Maiduguri
September - Gunmen kill 40 students at a post-secondary school in Yobe
December - Militants attack military installations in Maiduguri
January - Militants kill 74 people and burn down a village in attacks in Borno and Adamawa
February - Gunmen kill as many as 60 in attack on school in Yobe
April - Militants abduct 276 schoolgirls
In Washington , the U.S. State Department urged Nigeria to keep human rights in mind as it goes after the insurgents.
"We call on Nigerian officials to ensure that security forces protect civilians in a security response, in a way that respects human rights, and the rule of law. And to ensure that recent incidents in the north, including the violence in Baga,are fully investigated and those responsible are held accountable," State Department spokesman Patrick Ventrell said.
On Tuesday, President Goodluck Jonathan said Nigeria is facing a rebellion in the north and acknowledged that Boko Haram militants have taken over parts of Borno state.
Boko Haram has fought the government since 2009, killing hundreds of people in bomb and gun attacks that often target churches, officials, and law enforcement.
The disruptive group seeks to impose Islamic law across northern Nigeria.