Pakistan briefly reopened the Khyber Pass on Friday, three days after it was sealed off as part of a military offensive against Taliban guerrillas. The passage is the most important supply route for American and other NATO troops fighting the Taliban movement in neighboring Afghanistan. The main road through the pass, in northwestern Pakistan, was open for six hours on Friday morning and afternoon and was expected to be open for the same duration on Saturday, said Tariq Hayat, the top official in the Khyber Agency, the formal name for the surrounding political district. He said 800 cars, buses, tractors and cargo trucks traveled the road on Friday. "As our comfort zone increases, we will be easing off on the restriction of movement," Mr. Hayat said. "Right now, we are still in the middle of active operations." However, the critical test will not come until after the Khyber military operation is finished. Some militants are thought to have moved to other areas to avoid the offensive, and after similar military operations in western Pakistan, the guerrillas simply migrated back and resumed attacks once the troops departed. On Tuesday, beginning the military operation, Pakistani Frontier Corps paramilitary troops backed by helicopter gunships, tanks and artillery moved into Jamrud, a district on the main Khyber road just west of Peshawar, a frontier hub of three million people. They carried orders to dynamite or bulldoze homes belonging to men suspected of harboring or supporting Taliban militants or carrying out other illegal activities. By late Friday, the troops had arrested more than 70 people and had destroyed 45 homes, according to Mr. Hayat, who also said two children and one woman were killed the first day of the operation when an artillery shell landed near a house. He said the operation was now moving to the south and north of Jamrud.