The United States military has reached a deal to transfer power of its main detention center in Afghanistan over to the government there.

The transfer will take place over the next six months and is critical to defining a long-term relationship between the nations as the U.S. starts withdrawing troops.

The two sides have been in negotiations for months over a partnership deal. Afghan President Hamid Karzai had set Friday as the last day for the U.S. to hand over the 3,000 Afghans being held at the Parwan detention facility.

The U.S. will still have access to the facility and be able to block the release of any of the detainees.

Friday's announcement came two days after President Barack Obama said he believes it's time to begin moving America's troops out of Afghanistan.

Six Americans were killed recently in retaliation for accidental desecration of the Koran by U.S. troops.

"I think that it is an indication of the challenges in that environment, and it's an indication that now is the time for us to transition," Obama said during a White House news conference.

The president gave no indication that the U.S. would speed up the NATO-backed plan to end combat missions in Afghanistan at the end of 2014.