WASHINGTON — The White House said leaving Afghanistan is not an option President Barack Obama is considering.

White House spokesman Robert Gibbs said today Obama is not considering leaving the eroding war in Afghanistan. Obama is undertaking a thorough review of the U.S. policy in the war that is about to enter its ninth year.

Gibbs said it's clear the United States cannot simply withdraw.

The debate over whether to send as many as 40,000 more U.S. troops to Afghanistan is a major element of a strategy overhaul senior administration policy advisers will consider this week as they gather for top-level meetings on the evolving direction of the war.