President Bush has approved the deployment of 3,200 U.S. Marines to Afghanistan to help the NATO-led security effort in the south and to increase the number of trainers for the Afghan army and police. The Pentagon describes the deployment as a "one time, extraordinary" event. VOA's Al Pessin reports from the Pentagon.

The Pentagon says President Bush acted on a recommendation from Defense Secretary Robert Gates, who received the request from senior military commanders on Friday. Pentagon Press Secretary Geoff Morrell says the deployment in March and April will "greatly enhance" NATO's ability to deal with any spring offensive by the Taliban. "This has been timed to maximize our ability to take on the Taliban should they choose, unwisely I may add, to attempt a second spring offensive," he said.

Morrell says about 2,200 of the Marines will be a combat unit, available for NATO missions in southern Afghanistan, where alliance forces from other nations have been struggling to control Taliban influence and infiltration by al-Qaida units based in Pakistan. He says, the rest of the troops will be trainers, mainly for the Afghan National Police.

The arrival of the Marines could free up more than 1,000 U.S. Army troops who have been on loan to NATO in the south. Those soldiers could return to Eastern Afghanistan, where U.S. forces have the lead responsibility. That could help solidify security gains in the east, and also get better control of that part of the Afghanistan-Pakistan border.

The U.S. move comes after months of inaction by other NATO members to address a shortfall of more than 7,000 troops in their Afghanistan battle plan. The alliance agreed on how many troops were needed for its security and training missions in Afghanistan, but did not provide all of them.

As the largest contributor of foreign troops for the NATO mission, the United States has been pressing its allies to come up with the needed troops. The spokesman, Geoff Morrell, says Secretary Gates hopes the U.S. move to fill half the shortfall will inspire other NATO members to do more.

"We have gone a long way toward meeting that outstanding requirement with this deployment that we've just announced, an additional 3,200 forces. It is our hope that our allies in NATO and other partners involved in the efforts in Afghanistan will see what more they can do to add forces to bring down the shortfall that will exist even after we deploy these additional Marines," he said.

Morrell says the United States will work hard between now and the NATO summit in April to get members to provide the rest of the needed troops, and also to find troops to replace the U.S. Marines when they finish their Afghanistan deployment near the end of the year.

Morrell says it was difficult for the U.S. military to find the extra combat troops for Afghanistan, but he says improvements in security in Iraq, particularly in the west where the marines are in command, freed up some units for this deployment. Still, he stressed that the United States does not plan to continue with this additional commitment after this deployment ends.

Sending 3,200 Marines to Afghanistan will increase the U.S. commitment by more than 10 per cent to about 30,000, of the total of 55,000 foreign forces in the country. About half of the U.S. troops work within the NATO structure, most of them in eastern Afghanistan, and the rest conduct counter-insurgency and counter-terrorism operations throughout the country under U.S. command.