Update:

6:33 pm - To answer the headline's question, it appears NATO isn't sure yet. NATO secretary general Anders Fogh Rasmussen tells CNN's Wolf Blitzer that NATO will enforce the no-fly zone in addition to the arms embargo "in a couple of days" but that the alliance hasn't yet decided whether to enforce the broader U.N. resolution (read: air strikes).

After a week of disagreement over who would assume control of the U.N.-authorized military intervention in Libya once the U.S. steps into the background, the U.S., France, Britain, and Turkey have agreed on NATO taking over the mission by Monday or Tuesday, AFP reports. NATO has yet to officially announce its new role, as it confers with its 28 members to make sure all are on board.

In the lead-up to the deal, Turkey--NATO's only Muslim member--expressed concern that coalition air strikes in Libya were endangering civilians, and insisted that NATO, if it were to seize the reins of the operation, either halt air strikes or limit its mandate to enforcing a no-fly zone while a smaller coalition continued to bomb Libyan forces. Turkish officials even suggested that the West was intervening in Libya to secure oil and mineral wealth rather than to protect civilians, Reuters notes.

The terms of the agreement struck today are not yet clear, but Turkey's foreign minister was quoted on state television as saying "our demands have been met on Libya." If this is true, Turkey's support could alter the current rules of engagement in Libya. In other words, NATO's new responsibilities will spark a debate about how to define the U.N.'s instructions to "take all necessary measures ... to protect civilians and civilian populated areas" in Libya.

Turkey interprets the mandate as enforcing a no-fly zone and arms embargo and providing humanitarian aid, nothing more. As Prime Minister Recep Tayyip Erdogan declared on Thursday, "Turkish planes, Turkish soldiers will never be the ones firing bullets and dropping bombs on our brothers in Libya." Coalition forces, meanwhile, have interpreted protecting civilians to include assaulting Muammar Qaddafi's ground forces, as they've done in recent days.

Earlier on Thursday, Turkey's parliament voted to join NATO's enforcement of a U.N.-authorized arms embargo off the coast of Libya. In the photo above, NATO's supreme allied commander in Europe,  James Stavridis, meets with Turkish military chief Isik Kosaner before the vote.

ABC News reports that going forward, the U.S. will play a limited role in the campaign--contributing resources like tankers and personnel recovery teams.