BRUSSELS, July 26 (Xinhua) -- NATO troops are to take charge of security in southern Afghanistan after ambassadors agreed to the 26-nation military alliance's ambitious plans, NATO spokesman James Appathurai said on Wednesday.

    "Today the NAC (North Atlantic Council) gave provisional approval for the transfer of authority from forces in the south from the coalition to NATO," said Appathurai.

    The decision still needs the backing of non-NATO members such as Australia that contribute to the International Security Assistance Force in the southern Afghanistan.

    After that, the NATO (North Atlantic Treaty Organization) ambassadors will give final approval as expected Friday.

    "We expect that at or around the 31st of this month, NATO's operations will expand to the south," Appathurai said. "We will have at that point approximately 18,000 forces under NATO command in Afghanistan."

    NATO officials said that the operation in Afghanistan will be the most ambitious undertaking of the trans-atlantic alliance. Enditem