Kandahar, Afghanistan ? Between 50 and 60 suspected Taliban militants died Tuesday during the fourth day of a NATO-led offensive in southern Afghanistan.

The U.S. troops, operating under NATO command, clashed with the militants in the Panjwayi district of Kandahar province, where an offensive began over the weekend to flush out hundreds of Taliban fighters.

NATO already has reported more than 200 Taliban killed in the operation.

“The fight must be won and will be won,” NATO Secretary General Jaap de Hoop Scheffer said. “We should win because not winning means Afghanistan becoming a failed state again.”

De Hoop Scheffer acknowledged that NATO forces had met stiffer resistance than expected since they took command of the south from a U.S.-led coalition a month ago. “The spoilers are testing out NATO to see if NATO is as robust as the coalition. The answer, as we now see, is ‘Yes.”‘