The Pentagon has told its top commander in Afghanistan to delay submitting his request for additional troops, defense officials say, amid signs that the Obama administration is rethinking its strategy for combating a resurgent Taliban. A senior Pentagon official says the administration has asked for the reprieve so it can complete a review of the U.S.-led war effort. "We have to make sure we have the right strategy" before looking at additional troop requests, the official said. "Things have changed on the ground fairly considerably." Gen. Stanley McChrystal, the U.S. commander in Afghanistan, recently completed a classified report asking for significant numbers of new American troops. Military officials familiar with the matter say the report lays out several options, including one that seeks roughly 40,000 reinforcements, which would push the U.S. military presence in Afghanistan to more than 100,000 for the first time. But the commander has been told to delay submitting the troop request to the Pentagon at the direction of Defense Secretary Robert M. Gates and other top civilian officials, according to defense officials. The administration's call for a further strategic review -- which official said could take weeks -- comes as military commanders in the field say the campaign is running out of time and U.S. congressional and public support for the war is flagging. After weeks of speculation, details of Gen. Stanley McChrystal's report on Afghanistan were released. What's striking about his assessment, WSJ's Peter Spiegel reports, is the urgency of his message. In a new assessment of the war submitted to the Pentagon last month and made public Monday, Gen. McChrystal wrote that if the Taliban insurgency's momentum isn't reversed in the next 12 months, defeating it may no longer be possible. "Time matters; we must act now to reverse the negative trends and demonstrate progress," Gen. McChrystal wrote in a "Commander's Summary" at the start of the assessment. The senior defense official said the reviews are scheduled to be completed within the next few weeks. "There's a danger if you do this too quickly," he said. "But we all feel the sense of urgency." A spokesman for Gen. McChrystal didn't respond to a request to comment. Geoff Morrell, a spokesman for Mr. Gates, acknowledged that the defense secretary and other top officials are "working through the process" of how Gen. McChrystal's request will be submitted. Gen. McChrystal's call for quick action appears to be increasingly at odds with comments from President Barack Obama, who has insisted in recent days that he won't be rushed into approving more U.S. troops for the war. White House aides Monday again said there was no need for an immediate decision on troop levels for next year, adding that Mr. Gates and Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, have requested "at least several" meetings with the president on strategy before any final troop decisions. "Gen. McChrystal wants a very fulsome approach. He might be right on that. But we have other options, and we have to look at them," said a White House official. Mr. Obama's decision to put off a decision on further troop increases drew sharp criticism from Republicans in Congress. On Monday, party leaders attempted to raise pressure on the president to act, in part by insisting Gen. McChrystal come to Congress to testify on his findings. The Bush administration used a similar strategy to great effect with former Iraq commander Gen. David Petraeus. (WSJ)