NATO defense ministers on Thursday approved an extension of the alliance's Afghan security mission across the entire country, taking in the volatile eastern region and bringing up at least 10,000 U.S. troops under allied command, an official said.

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

NATO troops moved into the southern sector two months ago, sparking fierce resistance from Taliban fighters and dragging the alliance into the first major ground combat since it was formed six decades ago.

It will also bring to more than 12,000 the total number of U.S. troops under the command of British Lt. Gen. David Richards, the NATO commander in Afghanistan.

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That would be the largest number of U.S. troops brought under a foreign battlefield commander since World War II, U.S. officials said. However, overall control of the mission lies with NATO's supreme commander, U.S. Marine Corps Gen. James L. Jones, and a U.S. general is expected to replace Richards in February for a one-year rotation.

Appathurai said the plan to take NATO's mission nationwide showed the success of the operation despite the upsurge of Taliban violence that its troops are facing in the south and the difficulties the alliance has in persuading European nations to provide the extra troops its commanders need.

"What it shows is that this operation is moving forward," Appathurai told a news conference. "I think it demonstrates considerable success."

European ministers came under pressure at the meeting to send more troops to southern Afghanistan, where soldiers from Canada, Britain, the United States and the Netherlands have borne the brunt of the fighting.

"I will be urging NATO to look again to see what more can be done," British Defense Secretary Des Browne said before the meeting. "Allies must step up to the plate to meet our collective commitment to support the government and people of Afghanistan."

U.S. Defense Secretary Donald Rumsfeld is expected to make a similar call.

Officials said allies were expected to come forward with more troops although they may not fully meet the requirement of up to 2,500 extra soldiers backed by helicopters and planes which NATO's top commander, U.S. Gen. James L. Jones, has requested.

The 26 NATO defense ministers, gathering for a two-day fall meeting in Slovenia, are expected to reach an agreement Thursday on a plan to donate surplus military equipment to the Afghan army, which has units fighting alongside NATO forces against the Taliban.

Jones has been pushing for NATO to take over security operations in the eastern sector from the U.S.-led Operation Enduring Freedom. The move had been expected sometime this fall. It will not need NATO to muster significant numbers of extra troops because between 10,000 to 12,000 U.S. troops will switch to the alliance command.

Appathurai said the move will give commanders more flexibility by allowing them to deploy troops more freely around the country to places where they are most needed, because unlike some European countries, the United States does not impose restrictions on where in the country they are most needed.

The United States will continue its separate anti-terrorist mission to hunt down Taliban and al-Qaida operatives with about 8,000 troops.

The switch of command will take the NATO force to more than 30,000 troops. About 9,000 are engaged in the Taliban's former southern heartland, where allied commander admit the resistance from the fundamentalist insurgents has caught them by surprise.

On Tuesday, NATO said a Polish offer to gradually send 900 extra troops to serve as a mobile reserve force had gone a significant way to meet Jones' requirement for reinforcements. Romania and Canada have also offered a total of 400 extra troops, Appathurai said more are still needed.

Most of NATO's troops are operating in the relatively calm north and west to support reconstruction efforts. NATO is pushing nations such as Germany, Spain and Italy, which have troops in the north and west, to lift restrictions on where in Afghanistan their troops can operate and the type of missions they can carry out.