The U.S. has presented a draft resolution to the U.N. Security Council warning Sudan and South Sudan of sanctions if they do not implement an African Union peace plan to end fighting along their border.

The AU wants the Security Council to back its peace plan, passed earlier this week that calls for the two Sudans to settle their disputes over oil, citizenship and boundary issues within 90 days.

U.S. Ambassador Susan Rice says the Security Council was to begin discussing the U.S.-backed resolution on Thursday, “to provide swift and substantive support to the decision of the African Union.”

“From the United States' point of view, and I think from the point of view of many Council members, I think this is extremely urgent. And the Council ought to act with the speed that it's capable of in urgent situations.”

A copy of the draft text seen by reporters says the 15-member body would monitor implementation of the AU demands and could take “additional appropriate measures” under Article 41 of Chapter 7 of the U.N. Charter, which allows for sanctions.

Rice says the text will likely require “at least a few days” of discussion before going to a vote, noting that some Security Council members are skeptical about whether to impose what could be a binding security resolution.

The Security Council on Wednesday called for an immediate end to fighting along the border, which in recent weeks, has threatened to erupt into an all-out war between the former civil war foes.

Earlier this week, South Sudanese forces withdrew from the disputed oil town of Heglig, which they had earlier seized from Sudanese troops. Sudan is accused of carrying out an increasing number of bombings in South Sudan, which leaders in Juba say amounts to a declaration of war.

Sudan and South Sudan previously fought a 21-year civil war that killed more than 2 million people. The war ended with a 2005 peace agreement that included an independence referendum for the south.