WASHINGTON - NATO and Afghan troops have hit pockets of stiff resistance in Marjah, the Taliban's main stronghold in southern Afghanistan, and may need another month to fully secure the area, a NATO commander said on Thursday.

The Pentagon has voiced cautious optimism about the pace of the offensive but said Taliban holdouts appeared to be digging in for a fight to the death.

Four NATO troops were killed on Thursday alone, bringing the alliance's death toll to nine since the assault began on Saturday and underscoring the threat from hidden bombs and Taliban snipers. NATO did not immediately identify the nationalities of the four soldiers killed on Thursday.

The Marjah operation was at the end of the beginning, Major General Nick Carter, the British commander of NATO forces in southern Afghanistan, told reporters at the Pentagon by video link.

The offensive in Helmand province, Afghanistan's most violent, is meant to create a sense of momentum that will sweep eastwards towards Kandahar (in) the course of the next six months, he said, referring to the biggest population centre in the south.

Carter cautioned it would take up to one month more to fully clear the Marjah area and then three months to get a pretty fair idea about whether we've been successful.

The Helmand assault tests U.S. President Barack Obama's strategy of sending 30,000 more troops to seize insurgent-held areas before a planned 2011 troop drawdown begins.

'TO THE BITTER END'

U.S. Marines, as well as British and Afghan forces, are taking part in the operation, one of the biggest of the eight-year-old war.
As NATO and Afghan forces increase pressure on Taliban fighters around Kandahar, Carter said, insurgents were likely to turn more to asymmetric tactics such as suicide bombings.

Progress was slow and steady in Marjah due to mines and other explosive devices left by the Taliban, he said.

In Marjah itself there remains stiff resistance from the insurgents, Carter said. It will be some days before we can be completely confident that Marjah is secure.

Pentagon Press Secretary Geoff Morrell said the resistance did not appear very coordinated but there still are holdouts who have remained in Marjah and elsewhere in Helmand, who have stayed to fight, and they are clearly going to fight to the bitter end.

Pentagon war planners expect the offensive to last weeks.

Carter said fully securing Marjah from the Taliban could take us another 25 to 30 days but that NATO probably won't know for about 120 days whether or not the population is entirely convinced by the degree of commitment that their government is showing to them.

He acknowledged it was too early to say how the population will respond.

(Additional reporting by Phil Stewart; Editing by John O'Callaghan)

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