The United States has decided to reduce its troop presence in Afghanistan from 19,000 to 16,500 in March of next year, largely because of the increased role NATO is taking in providing security in the country.

US Army soldiers from Alpha Company, 1st Battalion, 508th Infantry (Airborne), prepare to move out on another mission in Mangritae(file photo)

Officials say U.S. Defense Secretary Donald Rumsfeld signed the orders late Monday, canceling the deployment of more than two thousand U.S. troops who were to go to Afghanistan early next year to replace a unit scheduled to leave.  The troops will continue their training, and will be ready to go if that becomes necessary.

The chief Defense Department spokesman Lawrence DiRita indicated that a variety of factors went into the decision, but he said the growing role of NATO is the key.

"This is being done largely because of the fact that NATO's role there is growing," he said.  "We've said all along that these force adjustments are conditions based.  And the conditions in Afghanistan are as follows:  there is an elected government, an elected parliament that's just been seated, a growing capability in [the] Afghan national army and security forces, and a growing responsibility, role for NATO.  And all of those conditions, the continued political and security development in that country, suggest that the U.S. can make this adjustment."

Mr. DiRita said the 16,500-strong U.S. force that will remain in Afghanistan includes thousands who will be part of the growing NATO security command in the country.  He said those outside the NATO force will focus on counterterrorism operations, and he said the force will be sufficient to perform that mission.  The effort includes offensives to attack remaining Taleban strongholds, and the search for senior al-Qaida terrorist leaders like Osama bin Laden.

Even with the reduction, the United States will continue to be the largest contributor of foreign forces to the Afghan security effort.  Afghanistan's own army now numbers 27,000, and the police force has about 55,000 members.

The U.S. commander in Iraq is also working on a reassessment of troop needs in that country, following last week's election and indications of increased capabilities in some Iraqi army units.  News reports indicate there could be a reduction of about 9,000 U.S. troops from the baseline of 138,000, which would be about 6.5 percent.  But officials say no decision has been made, and they will not say when it might come.