GWEN IFILL: The campaign to crush Taliban resistance in Afghanistan advanced on two fronts today. U.S. Marines pushed deeper into a key town amid reports a top Taliban official has been captured in Pakistan.
Margaret Warner begins our coverage.
MARGARET WARNER: Fifteen thousand NATO and Afghan troops made new gains today in their offensive in Southern Afghanistan. U.S. Marines and other forces linked up with units who had been air-dropped into Marjah when the operation began four days ago.
The Marines, moving in from the north, reported resistance weakening in the city of 80,000, a Taliban nerve center in Helmand province, and a hub in the opium poppy trade.
Correspondent Rajiv Chandrasekaran of The Washington Post, who is with a Marine unit in Marjah, reported that the fighting is less intense than it was.
RAJIV CHANDRASEKARAN, national editor, The Washington Post: But this place is a little quieter this evening. But, when the Marines from Bravo Company first arrived, they were welcomed, if will, by repeated small-arms attacks, grenades being shot into their compound.
When the Afghan soldiers who were with them trying to hoist the Afghan flag here, it was repeatedly shot at. But, since then, Marine commanders have dispatched another company, several hundred Marines worth of reinforcements to this area, and they have conducted operations aimed at trying to create a bit more of a buffer zone around the space today. It seems to have worked.
MARGARET WARNER: Still, snipers continued firing from hidden positions, and Marines proceeded cautiously, moving from house to house, looking for bombs and booby-traps.
RAJIV CHANDRASEKARAN: There was an expectation that they would be able to roll into some of these areas somewhat unopposed. And that's clearly not been the case.
But a big part of this deliberate strategy is aimed at keeping Americans alive out here. U.S. Marine convoys go very deliberately down the road to look for roadside bombs. When they are seeking to clear housing compounds, they're moving very carefully to send in explosive-sniffing dogs and other technicians to look for booby-traps.
The result has been remarkably few Marine casualties for such a large and complicated operation.
MARGARET WARNER: NATO and Afghan officials reported, three international troops have been killed so far, along with one Afghan soldier. And they confirmed three more Afghan civilians killed since Sunday.
There was also progress on another front, targeting the senior Taliban leadership, which is holed up in neighboring Pakistan. Word came that Mullah Abdul Ghani Baradar, the Afghan Taliban's top military commander, had been secretly captured 10 days ago in Pakistan.
The New York Times and others reported he had been hiding here, in the port city of Karachi. They said he was seized in a joint CIA-Pakistani operation and is being held and interrogated by the Pakistanis.
Though the story didn't break until last night, The Times learned of Baradar's arrest last week. The White House asked the paper to withhold the story, in hopes Baradar might reveal information about his fellow Taliban leaders before they learned of his capture.
At the White House today, presidential spokesman Robert Gibbs wouldn't confirm the arrest. But he did point to growing assistance from Pakistan in the fight against the Taliban.
ROBERT GIBBS, White House press secretary: I think we have, over the course of many months, seen an increase in that cooperation, and I think we've seen -- dating back, quite frankly, to last spring, we've seen an increase in Pakistani pushback on extremists in their own country, which I think is beneficial not simply for us, but I think the Pakistanis realize that extremist -- extremist threats within its own border were not just threats outside of its country, but were threats to their own country. And I think they have appropriately taken strong action.
MARGARET WARNER: Baradar was said to be commanding the Taliban's military operations in Afghanistan's southern insurgent heartland. And he was second only to the group's spiritual head, Mullah Mohammed Omar.
For its part, the Taliban denied Baradar had been captured or that NATO's offensive is gaining ground. A spokesman said: "This is just rumor spread by foreigners to divert attention from the Marjah offensive. They are facing big problems in Marjah. In reality, there is nothing regarding Baradar's arrest. He is safe and he is in Afghanistan."
In the meantime, NATO commanders were already looking past the immediate fight. U.S. Marines today secured the area in Marjah where they plan to establish a new government center, and pave the way for tribal leaders and others to meet and discuss the city's future.