ABUJA, Nigeria >> A Nigerian government official said "all options are open" in efforts to rescue almost 300 abducted schoolgirls from their captors as U.S. reconnaissance aircraft started flying over this West African country in a search effort.

Boko Haram, the militant group that kidnapped the girls last month from a school in Borno state, released a video Monday purporting to show some of the girls. A civic leader said representatives of the missing girls’ families were set to view the video as a group later on Tuesday to see if some of the girls can be identified.

According to a senior defense official in Washington, the U.S. is using a manned MC-12 surveillance aircraft, which is based in Niger, to conduct missions in Nigeria. In addition to the turboprop model which has seen heavy use in Afghanistan, U.S. officials are also considering the use of drones. At this point the surveillance missions are not continuous.

Gen. David Rodriguez, head of U.S. Africa Command, was in Abuja on Tuesday, meeting with leaders at the U.S. Embassy, the defense official said. The official was not authorized to discuss the matter publicly, so spoke on condition of anonymity.

Boko Haram’s leader, who appears separately from the girls, says in the new video: "I swear to almighty Allah, you will not see them again until you release our brothers that you have captured." He has previously threatened to sell the girls into slavery.

Hussein Monguno, an official with a civic group called the Borno Yobe People’s Forum, said representatives of the families of the missing girls had been invited to the Borno governor’s residence in the Nigerian capital of Abuja to view the latest Boko Haram video. The government is likely to communicate the next course of action if some family representatives "verify" that their children appear in the video, he said by phone from Maiduguri, the Borno capital.

Nigeria’s government initially suggested there would be no negotiations with Boko Haram, but it appears that stance may be relaxed.

Mike Omeri, the director of the government’s information agency, said the government will "use whatever kind of action" it takes to free the girls. He also warned that a military operation, with foreign help, was possible.

"At the moment, because all options are open we are interacting with experts, military and intelligence experts from other parts of the world," he said late Monday. "So these are part of the options that are available to us and many more."

The mass kidnappings — and the government’s allegedly slow response to find the missing girls — have sparked outrage at home and abroad. Last week critics organized a mass protest in Abuja to press the government to do more to find the missing girls and to stop attacks by Boko Haram.

The official News Agency of Nigeria reported that President Goodluck Jonathan on Tuesday asked the National Assembly to extend for another six months the state of emergency in Borno and two other northeastern states. The emergency was imposed May 14, 2013, and extended in December.

Britain and the U.S. are now actively helping Nigeria’s government to rescue the missing girls. Britain, which has dispatched security experts to Nigeria, said it is looking to offer "longer-term counter-terrorism solutions to prevent such attacks in the future and defeat Boko Haram."

The U.S. is sharing commercial satellite imagery with the Nigerian government and is flying manned intelligence, surveillance and reconnaissance aircraft over Nigeria with the Nigerian government’s permission, a senior U.S. official told The Associated Press on Monday.

Boko Haram has killed more than 1,500 people this year in a campaign of bombings, massacres and kidnappings.

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Associated Press writers Lolita C. Baldor and Matthew Lee in Washington and Rodney Muhumuza in Kampala, Uganda, contributed to this report.