WASHINGTON -- The Obama administration is imposing economic sanctions on five additional Libyan officials, including the prime minister and the ministers of oil and finance. The chief of staff to longtime leader Moammar Gadhafi and a security director are included.

The Treasury Department said Friday that the sanctions also apply to two entities owned or controlled by Gadhafi's children.

Obama froze the assets of Gadhafi and members of his regime in February to try to force Libya's longtime ruler from office. The Treasury Department said it has already frozen more than $34 billion in assets.

Earlier this week, the administration lifted financial and travel sanctions on Libya's foreign minister Moussa Koussa following his decision to defect and sever ties with Gadhafi.