WASHINGTON (AP) – President Barack Obama has approved adding about 17,000 U.S. troops for the flagging war in Afghanistan, administration, defense and congressional officials said Tuesday.

The Obama administration is expected to announce on Tuesday that it will send one additional Army brigade and an unknown number of Marines to Afghanistan this spring and summer. Officials spoke on condition of anonymity ahead of the official announcement.

About 8,000 Marines are expected to go in first, followed by about 9,000 Army troops.

The new forces represent the first installment on a larger influx of U.S. forces widely expected this year. Obama’s decision would get several thousand troops in place in time for the increase in fighting that usually comes with warmer weather and ahead of national elections in August.

The additional forces partly answer a standing request from the U.S. commander in Afghanistan, Gen. David McKiernan, who has sought as many as 30,000 additional U.S. forces to counter the resurgence of the Taliban militants and protect Afghan civilians.

The United States has slightly more than 30,000 troops in Afghanistan now.

The new units are a Marine Expeditionary Brigade unit from Camp Lejeune, N.C., and an Army Stryker brigade from Fort Lewis in Washington state.

Ahead of his first foreign trip, Obama told a Canadian news organization that the United States will seek a more comprehensive, diplomatic approach to Afghanistan, where the U.S. has been engaged in war since 2001.

“I am absolutely convinced that you cannot solve the problem of Afghanistan, the Taliban, the spread of extremism in that region solely through military means,” the president said in a White House interview with Toronto-based Canadian Broadcasting Corp.

Obama is scheduled to make a quick day trip to Ottawa on Thursday.