(Adds Obama comments, paragraphs 2, 4-5)

By Lesley Wroughton and Mark Hosenball

WASHINGTON, May 6 (Reuters) - The United States has offered to send an American team of experts to Nigeria to support the government's response to the kidnapping of more than 200 schoolgirls by an Islamist militant group, President Barack Obama's administration said on Tuesday.

"We're going to do everything we can to provide assistance to them," Obama told NBC News in an interview. "In the short term our goal is obviously to help the international community, and the Nigerian government, as a team to do everything we can to recover these young ladies."

The group Boko Haram kidnapped more than 200 schoolgirls last month and has threatened to sell them into slavery. Suspected Boko Haram gunmen kidnapped eight more girls from a village near one of the Islamists' strongholds in northeastern Nigeria overnight, police and residents said on Tuesday.

In a separate interview with ABC News, Obama called the kidnappings "heartbreaking" and "outrageous."

"This may be the event that helps to mobilize the entire international community to finally do something against this horrendous organization that's perpetrated such a terrible crime," he said.

Obama and the U.S. State Department said Nigerian President Goodluck Jonathan had accepted U.S. offers for assistance.

Secretary of State John Kerry said he had spoken to Jonathan by phone and offered to send a "coordination cell" that would include U.S. military personnel and law enforcement officials with expertise in investigations and hostage negotiations.

While the U.S. government previously offered to assist Nigeria in tracking the kidnapped girls, U.S. officials said the Nigerian government had not at first embraced those overtures.

Nigeria had "its own set of strategies in the beginning, and you can offer and talk but you can't do if the government has its own sense of how it is proceeding," Kerry told a news conference with EU policy chief Catherine Ashton.

"Now, the complications that have arisen convinced everybody that there needs to be a greater effort and it will begin immediately," Kerry said. "I think you will see a very rapid response."

It was unclear how extensive U.S. help to Nigerian authorities would be. Two U.S. officials, speaking on condition of anonymity, said U.S. intelligence information on where and how the kidnapped girls are being held was incomplete.

While U.S. government units, including intelligence agencies, have relationships with their counterparts in Nigeria, the contacts between such agencies are wary, restrained by issues of trust and politics, including concerns about the Nigerian government's human rights record.

HIGH-INTELLIGENCE TARGET

The U.S. officials said it was unlikely American assistance to Nigeria would include highly sophisticated intelligence-gathering equipment or ultra-sensitive intelligence information.

One official said U.S. dealings with Nigerian authorities would proceed with caution. But a second official said the United States would try to "err on the side of generosity" in providing assistance.

Historically, Boko Haram has been a high-priority U.S. intelligence target. A year-old document called the National Intelligence Priorities Framework, leaked to the media by former U.S. National Security Agency contractor Edward Snowden, lists three specific intelligence collection priorities related to the group.

The document, seen by Reuters, said U.S. spy agencies' top collection mission for Boko Haram was to acquire information related to "terrorism" - a topic given a priority of "1", the highest priority level.

Collection of information on Boko Haram's involvement in the acquisition of "advanced conventional weapons" is given a priority of "5", the lowest priority level, the document says.

Collection of intelligence on the group's interest in, or involvement with, "nuclear" weapons of mass destruction is given a priority of "3", although a U.S. source said Washington had no evidence today that Boko Haram had any involvement with nuclear weapons. (Additional reporting by Will Dunham and Steve Holland; Editing by Warren Strobel, James Dalgleish, Peter Cooney and Ken Wills)

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