Gates in Afghanistan to evaluate war progress.

KABUL, Afghanistan –  U.S. Defense Secretary Robert Gates arrived in Afghanistan Monday, beginning a two-day visit with U.S. troops, allied commanders and Afghan leaders to gauge war progress as the Obama administration moves toward crucial decisions on reducing troop levels.

Gates planned to travel to eastern and southern portions of Afghanistan, the areas most fiercely contested by the Taliban insurgency.

Defense Department spokesman Geoff Morrell told reporters flying with the Pentagon chief from Washington that Gates wants to get a first-hand feel for changes on the ground since he last was in Afghanistan in December.

The U.S. is committed to beginning a troop withdrawal in July. But the size and scope of the pullback will depend on the degree of progress toward handing off full control to the shaky Afghan government.

Morrell said Gates expects to hear from troops and commanders that U.S. and NATO strategy is making important progress against the relentless Taliban, who are thought to be gearing up for a spring offensive.

U.S. commanders have been saying for weeks that the Taliban are suffering big losses in territory and personnel, while being denied the funding and infiltration routes they have relied on in the past to ramp up guerrilla operations each spring.

Marine Maj. Gen. Richard Mills, top commander in the southwestern province of Helmand, told reporters last week that a Taliban counteroffensive is anticipated.

Mills said he expects the Taliban to try "to regain very, very valuable territory ... lost over the past six to eight months." He added that U.S. and allied forces are intercepting "as many of the foreign fighters as we can" who come from Pakistan to attack U.S. and Afghan troops.

Gates sees the spring as a potentially decisive period for President Barack Obama's war strategy, which includes beginning to withdraw U.S. forces in July.

This week's visit is Gates' 13th trip to Afghanistan, and probably one of his last as defense secretary. He has said he will retire this year but has not given a date.

After Afghanistan, Gates planned to fly to the Stuttgart, Germany, headquarters of U.S. Africa Command to attend a ceremony Wednesday marking the arrival of a new commander, Army Gen. Carter Ham.

Gates will attend a NATO defense ministers meeting in Brussels on Thursday and Friday.