About 15,000 NATO and Afghan troops are taking part in the offensive around Marjah, a town of about 80,000 people that was the largest population center in southern Helmand province under Taleban control. NATO hopes to rush in aid and public services as soon as the town is secured to try to win the loyalty of the population.

The arrest of top Taleban military commander Mullah Abdul Ghani Baradar, confirmed by Pakistan on Wednesday, could deal a huge blow to the insurgency that is trying to bring down the Afghan government and evict foreign troops.

But on day five of Operation Mushtarak (“Together”) officers said progress has slowed because of multitudes of hidden bombs in the farming district of Helmand province that drug lords and the Taleban have controlled for years.

The top Afghan general commanding Operation Mushtarak also accused the Taleban of hiding behind human shields.

“They have taken people hostage. Our troops have seen them putting women and children on the roofs of houses and firing from behind them,” said General Moheedin Ghori, commander of the 4,400 Afghan troops taking part. “We have strict orders not to fire at civilian areas,” said Ghori.

A Taleban spokesman denied their fighters were exploiting civilians. “We have never used civilians as human shields, we do not use our own people as human shields,” Yousuf Ahmadi said by telephone from an undisclosed location. “We are there, standing against the invaders in direct fighting.”

A Marine spokesman said the zone appeared quieter Wednesday than on previous days, but was likely to flare up again.