WASHINGTON - US Defense Department officials on Wednesday said terrorist groups are trying to gain hold in Libya, but has been so far rejected by the Libyan National Transitional Council (NTC).

The officials made the assessment in a Pentagon background briefing, saying terrorist groups are "always looking for a target of opportunity."

The officials said the NTC has rejected the terrorist groups and "it certainly seems that they have gone to great lengths to disassociate themselves."

Terrorist groups have expanded in other parts of North Africa, including al Shabaab in Somalia, Boko Haram in Nigeria, and al-Qaida in the Islamic Maghreb, an Algerian-based group believed to be working with Tehrik-e Taliban Pakistan, according to the officials, who briefed media in condition of anonymity.

The U.S. officials said intelligence officials are studying the degree to which terrorist splinter groups are working together.

"They'll remain a concern," said one Defense Department official. "There is an element of defeating the organization ... that is separate from the ideological component. You can get them to be operationally incapable, but that doesn't destroy the idea of al-Qaida."