WASHINGTON - The Pentagon has notified more than 35,000 Army soldiers to be prepared to deploy to Iraq beginning this fall, a move that would allow commanders to maintain the buildup of troops through the end of the year if needed.

Pentagon spokesman Bryan Whitman said the deployment orders, which Defense Secretary Robert M. Gates has signed, did not mean that the military has decided to keep the increased level of 20 brigades in Iraq through December. A brigade is roughly 3,500 soldiers.

Instead, he said yesterday, the decision gives the Pentagon the "capability" to carry the buildup to the end of the year. The replacement forces, he said, would give commanders in Iraq the flexibility they need to complete the mission there.

Whitman said the announcement had "nothing to do" with a decision to extend the troop buildup. He said the Pentagon "has been very clear that a decision about the duration of the surge will depend on conditions on the ground."

Early this year, President Bush ordered about 30,000 additional troops to Iraq to quell spiking violence, particularly in and around Baghdad. Gates and his military leaders have said that commanders in Iraq will make recommendations in September on whether the buildup has been successful and whether it should continue or if troops can begin coming home.

According to the Army, the combat brigades would deploy for up to 15 months. The Army also said that about 1,000 additional support troops from the Army Reserves would deploy in August.