BAGHDAD (AP) – About 12,000 U.S. soldiers will leave Iraq by September, officials said Sunday, hours after a Baghdad suicide bomber killed about 30 people in a chilling reminder of the nation’s still-shaky security.

The withdrawals, which will most likely come from Baghdad and Anbar province, once main battlefields of the war, are the first step in keeping with President Barack Obama’s pledge to end America’s role in the war.

That would bring U.S. troop levels to more than 120,000.