The United States is sending 1,400 more Marines to Afghanistan in an effort to consolidate gains and apply further pressure on the Taliban during the current winter campaign.

Pentagon officials said yesterday that the Marines are expected to go within weeks, ahead of a possible escalation in fighting during the spring. The Marines could arrive within weeks but they are only expected to be in Afghanistan for a 90-day deployment.

Last month, Mr. Obama said enough progress was being made in the war to meet his pledge of starting a withdrawal of some U.S. troops by July and handing over security to the Afghan government by 2014.