Joint Chiefs of Staff Chairman Adm. Mike Mullen tamped down talk that the U.S. may increase troop levels in Afghanistan in a tweet Saturday.

Mullen played down an upcoming report from Gen. Stanley McChrystal, the commander of the international security force in Afghanistan, which may request more forces for the country.

Mullen dismissed the speculation over the content of McChrystal's report on his Twitter account on Saturday.

He tweeted:
Speculation about Gen. McChrystal asking for more troops is just that: speculation. Work isn't done yet, need to let him finish it.

Reports have swirled
, though, that McChrysal will do just that -- especially after troops in Afghanistan incurred their worst fatality toll in years.

The report would also put President Obama in a difficult political position, perhaps forcing him to choose between any recommendation McChrystal might make and political weariness over escalating the military situation in Afghanistan, which is approaching its 8th anniversary this fall.

Cross-posted to the Twitter Room.