NATO assumed command of security across the whole of Afghanistan on Thursday when it took over from U.S.-led forces in the east of the country. The transfer of power took place as the bodies of two Canadian soldiers killed this week were sent on their way home.

The commander of the NATO-led force, British Lt. Gen. David Richards, called the move "historic" in a ceremony attended by Afghan President Hamid Karzai and U.S. Lt. Gen. Karl Eikenberry, the top U.S. military commander in Afghanistan.

"The unity of command that today's transition brings should enhance the effectiveness of the overall operation," the commander of NATO's Afghan force, Richards said in a speech at a change-of commander ceremony in Kabul.

"ISAF has shown it has the resolve to meet the challenges of its expanded mission," he said, referring to fighting in the south since NATO took command there at the end of July.

The transfer had been expected later in the year, but alliance officials said battles with resurgent guerrillas in the south showed the pressing need to consolidate the troops under NATO.

NATO Secretary General Jaap de Hoop Scheffer said Thursday the move will make the operation in the east more efficient.

"NATO brings in twice the force that the coalition had in the area. And nobody, be it Taliban or be it drug lord, will appreciate very much if he sees forces coming in and chasing him out and depriving him of whatever activity that he might be engaged in," he said.

The military alliance already commands troops in the north, west and south of Afghanistan, as well as its capital Kabul.

The U.S. will remain the biggest contributor to NATO's 33,000-strong force in the country, with more than 13,000 troops.

The U.S. is to retain control of some 8,000 of its troops - those tracking al Qaeda terrorists or involved in air operations.

"It really doesn't mean anything for the Canadian soldiers here, they will continue with their mission the way it is. It is a fairly significant I would say, for NATO," CTV's Paul Workman reported from Afghanistan.

"Essentially now the Americans have given up control of the mission in Afghanistan here, they have not left, their soldiers are still here but the overseer of all of this will be a NATO-appointed general," Workman said.

Canada has about 2,300 soldiers in Afghanistan, with most of them stationed in the south.

The command consolidation limits direct U.S. control to the sprawling American base at Bagram. A U.S. Army helicopter unit based at Kandahar airfield also will remain under American supervision.

U.S.-operated prisons and interrogation centers at Bagram will remain under U.S. oversight, while NATO will continue to transfer its detainees to Afghan police.

"Certainly there has been a change in the way this mission is being fought. It's not just Americans forces anymore, it's Dutch forces, and Canadian forces and British forces and it's a mixture of national armies," Workman said.

"I suppose that is causing some difficulty for command and that is why NATO has now taken over and it will have a centralized command."

NATO took charge of southern Afghanistan just two months ago and has struggled to stem escalating violence.

An American four-star general, Army Gen. Dan K. McNeil, will take charge of both U.S. and NATO forces in February, provided he is confirmed by the U.S. Senate.

NATO's combat role in southern Afghanistan is the largest the alliance has ever undertaken.

The transfer of power came as the bodies of Canadians soldiers, Sgt. Craig Paul Gillam and Cpl. Robert Thomas James Mitchell, were sent on their way home.

About 1,500 soldiers, most of them Canadian, lined the runway just after sunrise on Thursday as pallbearers carried the flag-draped caskets to an aircraft for the flight to Canada from the Kandahar base.

With files from The Associated Press