U.S. Defense Secretary Robert Gates has reassured NATO allies that the United States is committed to its mission in Afghanistan, even though the White House has yet to decide whether to send more American troops there.

The Pentagon chief told a group of NATO defense ministers in Slovakia Friday that it is "vastly premature" to draw conclusions about a new U.S. strategy for Afghanistan.

US Defense Sec. Robert Gates (L) and Gen. Stanley McChrystal (R) exchange a word at a NATO defense ministers meeting in Bratislava, 23 Oct 2009Gates said the Obama administration is studying whether to refine its current approach in light of the political situation in Afghanistan, but he said any U.S. troop reduction is unlikely.

A top U.S. commander in Afghanistan, General Stanley McChrystal, has recommended President Barack Obama send more troops, but Mr. Obama is closely monitoring events in Afghanistan before making a final decision.

Massive fraud in the August election led officials to call for a runoff vote between President Hamid Karzai and former Foreign Minister Abdullah Abdullah.

Earlier, NATO Secretary-General Anders Fogh Rasmussen urged alliance members to fully support the war effort in Afghanistan so that Afghan forces can take more responsibility.

Rasmussen told reporters that "sooner rather than later" NATO forces will take a supporting role, with Afghan forces in the lead.

Defense Secretary Gates is pushing a similar message.

Separately, the top U.N. envoy for Afghanistan, Kai Eide, said Afghan officials have barred poll workers who committed fraud in the first round of voting from participating in the runoff.

Speaking on the sidelines of the NATO meeting, Eide said fraud is still likely to occur during the second-round vote, but hopefully to a lesser degree. 

Some information for this report was provided by AP.