The 1,300 Marines -- a battalion and helicopter unit -- would be the only combat troops to shift from Iraq this year. However, a senior military official said the Marines were likely to be sent to western Afghanistan in November, not the more turbulent east or south.
They would replace the 2nd Battalion of the 7th Marine Regiment, based in Twenty-Nine Palms. Officials are not planning to replace another Marine contingent in the country's most troubled area, Helmand province in southern Afghanistan.
In sum, the Marine shifts actually represent an overall decline of about 2,000 U.S. combat troops in Afghanistan. The arrival there in February of the brigade from the Army's 10th Mountain Division would then amount to a net increase in combat troops.
Adm. Michael G. Mullen, chairman of the Joint Chiefs of Staff, has said his top priority for Afghanistan would be military trainers for Afghan security forces, suggesting a portion of those troops may be assigned to noncombat missions.
White House Press Secretary Dana Perino said Bush had received the military's recommendation on troop levels during a meeting Wednesday evening with Mullen and Defense Secretary Robert M. Gates, who presented Petraeus' plan.
"The question on the president's mind has been: How do we make sure that we cement those gains [in Iraq] and not jeopardize those gains, and be able to continue the process of return on success?" she said.