KABUL, Afghanistan — The 30 U.S. troops killed when their Chinook helicopter was shot down Saturday in eastern Afghanistan — many of them Navy SEALs &mash; were fighting a war rarely talked about.

They were not battling Afghanistan’s ingrained corruption, or building new roads or crafting nascent local governments. They were part of a group of elite troops that operate stealthily in the night and go after the U.S.’s most wanted targets of the war.

It was the worst single-day toll for American forces in Afghanistan since U.S. troops entered that country nearly 10 years ago, and one of the largest tolls in a single incident of either the Afghan war or the fighting in Iraq. Another seven Afghan troops also died in the crash. An interpreter was also killed; in all 38 people and a SEAL dog died in the crash.

The Associated Press reported that some of the SEALs were from SEAL Team 6, the same unit that provided the troops for the May 2 raid that killed al Qaida founder Osama bin Laden, but that could not be verified independently. The Pentagon released no information on the dead as officials worked through notifying 30 families of their loss.

U.S. officials in Afghanistan provided no details, but a senior Pentagon official in Washington confirmed that the helicopter had been shot down, though he said he could not provide details. Every night, scores of helicopters like the blasted Chinook leave bases and land amidst Taliban strongholds in remote areas, chasing local Taliban or terrorist leaders. Their activities rarely get reported, even when they are successful, with the notable exception of the May killing of al Qeada leader Osama bin Laden.

Instead, the discussion about the war focuses on whether such captures and kills by SEALs lead Afghans to reject the insurgents gripping their communities and instead to embrace a democratic system that is less likely to house insurgents. Afghans have come to expect such stealthy operations. A villager in the area where the helicopter went down told McClatchy he heard rocket fire. He said he later saw the helicopter burning in an orchard about a half-mile from his home. "Smoke was rising from the helicopter till morning," Mansour Majab said. Majab told McClatchy that night raids by U.S.-led forces happen frequently. "Every night the helicopters are flying over our house," he said by phone. He said on Thursday U.S. troops conducting a night raid in another village killed three Taliban fighters. He said Taliban forces fired a rocket at the downed helicopter.

"I was in the house and taking some food for the guests who were in our house. I heard the sound of a rocket firing,” Majab said. "Later we saw a helicopter downed in an apple and apricot orchard about a kilometer away. There is a river between our house and the place where the helicopter was downed. Smoke was rising from the helicopter till morning." Majab said that "most people are awake during night because of night raids" and that the region is dominated by the Taliban. "From each house at least one person is with the Taliban," he said.

In a conflict defined by U.S. troops who spend as much time nation-building as destroying the enemy, those killed Saturday were among the few forces that focus strictly on capturing and killing an enemy. That so many of the military's most elite forces were killed will have a marked impact on special operations in Afghanistan. It takes years to train a Navy SEAL unit, and those SEALs killed on the Chinook will reverberate across the force.