Taliban forces fighting U.S. troops in Afghanistan have grown stronger and more sophisticated, and are directing operations from neighboring Pakistan, a senior U.S. commander said on Wednesday.

More than four years into the war in Afghanistan, an operation often overshadowed by the focus on Iraq, the top U.S. commander there said the Taliban has grown in the south and reconstituted itself elsewhere. It is displaying better military command and its leaders remain elusive, he said.

Lt. Gen. Karl Eikenberry, commanding General, Combined Forces Command in Afghanistan, right, testifies on Capitol Hill, Wednesday, June 28, 2006 before the House Armed Services Committee hearing on the status of security and stability in Afghanistan, Defense Principle Deputy Assistant Secretary for International Security Affairs Mary Beth Long, center, and Drug Enforcement Administration Administrator Karen Tandy, look on. (AP Photo/Manuel Balce Ceneta)

"The fact remains that we're up against an enemy that is able to operate very effectively on both sides of the border," Lt. Gen. Karl Eikenberry said in testimony to U.S. lawmakers. "There's areas that they're able to stay within and to direct combat operations against ourselves and against the Afghan National Army."

Despite growing violence funded, U.S. officials say, by drug money, NATO will take over military operations in southern Afghanistan in July, according to Mary Beth Long, the Defense Department's principal deputy assistant secretary for international security affairs.

Ultimately, NATO rather than the United States will play the lead military role throughout Afghanistan. Long did not offer lawmakers a timeline, saying NATO would take full responsibility when conditions were "right."

The planned transition to NATO's military leadership will allow the United States to bring home some of its 23,000 troops in Afghanistan, a Pentagon spokesman said.

But in his public testimony, which preceded a closed-door classified briefing to lawmakers, Eikenberry did not discuss troop levels or offer a timeline for their drawdown.

While the U.S. military had disclosed plans in December to cut its contingent from 19,000 to about 16,500 this spring, troop levels remain higher. Including troops from other countries, the coalition force on the ground numbers 28,000, Eikenberry said.

Defense Secretary Donald Rumsfeld said U.S. troop levels may continue to climb.

"The number of troops that we have there and that other coalition countries have there are, in fact, going up," he told reporters on Wednesday. "As NATO took over the north, took over the west, is now in the process of taking over the south, they have actually increased the number of troops."

But Democrats challenged U.S. plans and operations in the face of a re-emerging Taliban.

"I do not see a long-term comprehensive strategy from the administration," said Rep. Ike Skelton of Missouri, the top Democrat on the committee. "And if one exists, it is not being clearly communicated to Congress, the American people or the people of Afghanistan."

Copyright © 2006 Reuters Limited

###