(AP) - President Barack Obama says he'llwithdraw America's combat brigades from Iraq over the next 18months.

He made the announcement in a speech to military troops andofficers at Camp LeJeune N.C. He said his administrationwill "proceed cautiously" on the withdrawal and that U.S.commanders will bring it about in close consultation with the Iraqigovernment.

During his campaign for the presidency, Obama had advocatedpulling troops out within 16 months of taking office. The timelinehe announced Friday, involving roughly 100,000 troops, was twomonths longer. It still hastens the U.S. exit, nevertheless.

Obama also said that between 35,000 and 50,000 troops willinitially remain there to help train Iraqi forces and undertakecounter-terrorism missions.