by Rajiv Chandrasekaran

MARJA, Afghanistan -- Lt. Col. Cal Worth, who commands one of two Marine battalions leading the offensive against Taliban fighters here, set off at 7 a.m. Wednesday for the return journey to his battalion headquarters from a combat outpost less than four miles away.

In a place where homemade bombs are buried under seemingly every road, this trip was supposed to be safe and easy: A team of Marine engineers and explosives-disposal experts had swept the route 48 hours earlier, unearthing and blowing up seven mines. But Worth's convoy had traveled less than a mile before the engineers discovered a mine on the rutted road. They would later find three more, all planted in the same intersection as the seven mines they found Monday.

Worth's Sisyphean challenge of moving about in Marja suggests that Taliban bombmakers, and those who bury the devices in the dirt roads here, have not been cowed by the presence of the Marines and a large contingent of Afghan soldiers. Nor have scores of other insurgent fighters, who kept up a steady pace of attacks on coalition forces Wednesday, firing assault rifles and rocket-propelled grenades at coalition bases and patrols.

Although U.S. and Afghan forces have made steady inroads here since beginning the largest joint military operation of the war four days ago, they control only a few modest patches of this farming community, principally around the two biggest bazaar areas. Much of Marja has not yet been patrolled by troops on the ground, and video images from surveillance drones have shown Taliban fighters operating with impunity in those places.

U.S. and NATO commanders were not certain whether the insurgents who have lorded over Marja for the past three years would stay and fight, or flee to parts of Afghanistan with fewer international security forces. It appears clear, however, that many Taliban members here have opted to stay -- at least for now.

That may mean many more weeks of arduous house-to-house clearing operations for Marines and Afghan forces in this 155-square-mile area, making this a far more complex and dangerous mission than initially envisaged, and possibly delaying some efforts to deliver government services and reconstruction projects to the 80,000 people who live here.

"It's early days yet," said British Maj. Gen. Nick Carter, the top allied commander in southern Afghanistan. "You're dealing with a large area, with a lot of people in it. It's going to take a while to clear it."

Even if insurgents are not fleeing, they are also not winning any of their fights with the Marines. Dozens of militants -- there is no authoritative count -- have been killed since the operation began. One Marine has died.

Senior U.S. military officials have been encouraged by the relatively low level of coalition casualties -- more Marines have been evacuated for hypothermia and knee or ankle strains than for gun and bomb wounds -- and by the fact that combat engineers have discovered dozens of roadside bombs that could have struck tactical vehicles.

The low level of injuries is due, in large part, to the Marines' deliberate approach in moving about the area. Instead of driving all over, hunting down insurgents, they have been traveling in cautious convoys that are preceded by sophisticated mine-sweeping gear.

Marine commanders remain optimistic that their initial efforts at establishing bubbles of security around key commercial areas will have a catalyzing effect on the population and will result in residents pointing out Taliban fighters, bomb locations and arms caches.

Thus far, however, most residents seem to be opting for a wait-and-see approach. Most roads used by the Marines have been devoid of people, save for a few curious gawkers. The bazaars are similarly abandoned, some so hastily that merchants left their onions and potatoes sitting atop wooden carts.

When Worth departed from his Bravo Company's base next to the Koru Chreh bazaar at 7 a.m., he figured he was giving himself more than enough time to make it back to headquarters by 10 a.m. for what was to be the first meeting of shopkeepers and community leaders. Next up on his schedule, at noon, was a visit from Carter, the top Marine commander in Afghanistan and the governor of Helmand province.

By 9:30, his convoy had ground to a halt when the engineers found the first bomb at a narrow intersection. At 10:30, while munching pretzels in his armored truck, he received a radio message: The meeting of shopkeepers "was a no-show. Nobody came."

When Carter and the dignitaries arrived at his headquarters, Worth was still sitting on the road, waiting for the ordnance-disposal experts to defuse the fourth bomb of the day. Turret gunners spotted several men milling about in the bushes, and Worth feared an ambush. To make matters worse, one of the convoy trucks accidentally drove halfway into a canal, further exposing the forces.

The group finally got moving, but by then a group of Afghan soldiers had already raised their red, green and black flag in the bazaar for the dignitaries. The governor and the visiting generals walked around the rubble of the market -- large parts of which were destroyed by a U.S. Special Forces airstrike in spring 2009 -- and hailed the progress of the current mission.

"I have full confidence that Marja district will be very peaceful, and it will be one of the best-developed districts in Afghanistan, " said Gulab Mangal, the Helmand governor.

When Carter was asked how long it would take to pacify Marja, he said: "You can't put a time on it. You just have to take it slowly but surely, and the people will be won around in due course."

Worth missed all of it. He arrived 30 minutes after they departed -- and 7 1/2 hours after he set off.

After the dignitaries left, the Afghan soldiers who raised the large, shiny tricolor pulled it down and replaced it with a smaller, faded one.

"It's still dangerous in this area," one soldier said. The Taliban "might burn it."