"Once those elections are completed, we will then begin the final drawdown," the Defense secretary said in Brussels.

The troops have been deployed to support the ongoing efforts to rout Islamist militants in Mali. 

The warning from Jay Carney came after a United Nations watchdog accused Iran of moving to speed up uranium enrichment.

Republicans last week blocked Hagel’s confirmation from proceeding, which was the first ever filibuster of a Defense secretary nominee.

The White House press secretary on Thursday called the delay on a vote for Hagel's nomination a "waste of time." 

NATO military leaders are reconsidering plans to slash the number of Afghan National Security Forces in the run-up to the U.S. withdrawal from the country next year, opting to maintain the Afghan force at current levels through 2018. 

Tehran has significantly ramped up its ability to produce potentially weapons-grade nuclear material, just as Iranian negotiators prepare for the latest round of negotiations with world leaders. 

The senators said in a letter to the president Thursday his Defense nominee lacks a broad base of bipartisan support.

Air Force Gen. Philip Breedlove is expected to be nominated as the next NATO supreme allied commander in Europe post now that Gen. John Allen is retiring, according to reports.

Senior NATO officials told the New York Times in Brussels that Breedlove is emerging as President Obama’s pick for the top NATO military post.

Pentagon press secretary George Little said Thursday that no decisions have been made, however.

Allen, who said this week his is retiring from the military, was in line to take the NATO post last year before he became ensnared in the scandal that led to the resignation of former CIA Director David Petraeus.