SLOVENIA ? A plan approved Thursday to extend NATO’s military control across all of Afghanistan would put as many as 12,000 American troops under foreign battlefield command, a number that U.S. officials said could be the most since World War II.

Defense Secretary Donald H. Rumsfeld hailed the change as a “bold step forward.”

The move is expected to take place in the next few weeks, NATO spokesman James Appathurai said.

The ministers also agreed to provide substantial amounts of military equipment for the Afghan army.

Rumsfeld said at a news conference that some countries had stepped forward in response to appeals from NATO commanders for as many as 2,500 more troops to join the operation against the Taliban in the south. But he said more were needed.

NATO-led troops took command of the southern portion of Afghanistan just two months ago and have been struggling to stem the escalating violence there.