LAGOS, Nigeria - WASHINGTON (CNN) -- The United States is offering its help, but making clear it is up to the Nigerian government to take the lead in rescuing more than 200 schoolgirls kidnapped by the Islamist militant group Boko Haram.
Officials told CNN that the Obama administration is sharing intelligence with Nigerian authorities and could provide other help, but there is no planning to send U.S. troops.
President Barack Obama is being briefed on the matter, and pressure is mounting worldwide for the Nigerian government to act.
On a trip to Africa, Secretary of State John Kerry said the United States "will do everything possible to support the Nigerian government to return these young women to their homes and to hold the perpetrators to justice."
In Washington, officials said the Obama administration was helping, but they didn't go into a lot of specific detail.
"We are going to keep working with the Nigerians privately on that," State Department spokeswoman Marie Harf told reporters. "Obviously they have come out very publicly and said that they are, you know, making every effort to find these girls. I just don't think we are going to outline how we are helping them. What we are focused on is making sure they can find them and bring them home to their families."
No U.S. troops
Asked if she anticipated U.S. troops or other assets getting sent to Nigeria, Harf replied: "I do not."
White House spokesman Jay Carney mentioned a series of U.S. programs and steps in Nigeria, most predating the latest kidnappings, intended to strengthen its criminal justice system, improve its ability to combat improvised explosive devices (IEDs) and expand economic opportunity for women.
"There are other things, I am sure ... but this is an outrage and a tragedy and we are doing what we can to assist the Nigerian government to support its efforts to find and free the young women who were abducted," Carney said.
According to two senior U.S. officials, Nigerian authorities so far have not asked for specific help in any kind of possible joint rescue mission. One of the officials said the Nigerians privately indicated they want to handle the situation themselves, perhaps because they don't want visible American forces in their country.
"We are sharing intelligence that may be relevant to this situation," said another U.S. official with direct knowledge of the situation, speaking on condition of not being identified due to the sensitive nature of the information. "You are going to see a focus on this in all three channels of government: diplomatic, intelligence and military."
The United States could offer satellite imagery and electronic intelligence such as communications intercepts in the effort to rescue the kidnapped girls. Another American official said the U.S. military is not planning to send troops, but could consider helping Nigerian forces with any planning for a rescue mission, under existing military cooperation agreements.
U.S. Africa Command has long been helping Nigerian forces improve their training and operations to counter Boko Haram militants.
Last week, the State Department's annual report on global terrorism described Boko Haram as a group that "espouses a violent Sunni extremist ideology" and has received funding from al Qaeda in the Islamic Magreb.
The United States designated Boko Haram a terrorist organization last November, said the report, which blamed the group for attacks in northern and northeastern Nigeria that have killed thousands of people since 2009.
Among the most notorious attacks by Boko Haram were a 2011 bombing at a United Nations building in Abuja that killed more than 20 people, and a wave of bombings in Kano, Nigeria, in 2012 that killed 180 people in one day, the State Department report said.
The group also has freed prisoners and killed students and soldiers in other attacks, and kidnapped French citizens in neighboring Cameroon, according to the report.
Link to al Qaeda affiliates
Boko Haram "receives the bulk of its funding from bank robberies and related criminal activities, including extortion and kidnapping for ransoms," as well as the al Qaeda in the Islamic Magreb funding, the report added.
According to U.S. authorities, Boko Haram has gotten training in weapons and communications from AQIM as well as al Qaeda in the Arabian Peninsula.
Last week, Attorney General Eric Holder asked U.S. intelligence agencies to prepare a report for him on the latest schoolgirl kidnappings in Nigeria, an American law enforcement official told CNN.
The attorney general also requested an assessment of Boko Haram that could help the Justice Department seek indictments or curtail funding sources for the group.
The name Boko Haram means "Western education is sin," and a video made public Monday showed a man claiming to be Boko Haram leader Abubakar Shekau saying the kidnapped girls should get married instead of going to school.
"I abducted your girls. I will sell them in the market, by Allah," the man says in the video first obtained by Agence France-Presse.
"There is a market for selling humans. Allah says I should sell. He commands me to sell. I will sell women. I sell women," he continues, according to a CNN translation from the local Hausa language.
According to accounts, armed members of Boko Haram overwhelmed security guards at a school in northeastern Borno state, pulled the girls out of bed and forced them into trucks. The convoy then disappeared into a forest bordering Cameroon.
The total number kidnapped was 276, according to Nigerian authorities. At least 53 escaped, leaving 223 missing, police said.
Nigerian President Goodluck Jonathan said Sunday that his government would free the girls.
In Washington, a group of U.S. senators from both parties has introduced a resolution condemning the kidnappings and calling for the United States to help the Nigerian government improve school security and go after Boko Haram.
The resolution stops short of calling for sending American troops, instead urging "timely civilian assistance" from the United States and allied African nations to help rescue the abducted girls.
"Attacking and abducting young women simply for going to school is despicable and must never be tolerated," Sen. Barbara Boxer, a California Democrat, said in a statement. "The international community must make clear that all children deserve the chance to pursue an education without fear and that those responsible for these heinous crimes will be held accountable."
CNN's Evan Perez, Elise Labott, Virginia Nicolaidis and Halimah Abdullah contributed to this report.
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