UNITED NATIONS — The Security Council committee that monitors sanctions against Libya agreed on Thursday to unfreeze $1.5 billion in Libyan assets for emergency aid to the country, where rebel forces that have ousted Col. Muammar el-Qaddafi are confronting a humanitarian crisis as they attempt to establish security and form a new government.

The committee’s decision came after South Africa, a committee member that has enjoyed close ties with Colonel Qaddafi and expressed doubts about the credibility of the rebel forces , dropped its opposition to releasing the assets. Unanimous consent by committee members was required.

Western diplomats said South Africa agreed to go along with the move after language in the decision was revised to state that the assets will be disbursed to the “relevant authorities” instead of the Transitional National Council, the opposition group in Libya that has been leading the struggle against Colonel Qaddafi. South Africa has not recognized the Transitional National Council as the legitimate government of Libya.

Earlier Thursday the United States, which had been pushing the committee to release the assets, had threatened to bypass the committee and submit a resolution to the full 15-member Security Council to achieve the same result. American diplomats had said they were confident they would have secured the nine votes needed for passage.