(Updates with quote from resident)
By Jibran and Ahmad
PESHAWAR, June 30 (Reuters) - The Pakistani army said it launched a ground offensive on Monday in a northwestern city considered a key Taliban stronghold after two weeks of aerial bombing.
A military statement said soldiers had found underground tunnels and bomb-making factories in Miranshah, the capital of North Waziristan.
"After the evacuation of all the civil population, a ground operation commenced in and around Miranshah early morning today," it said. "A house to house search of Miranshah town is being carried out by infantry troops and special service group."
Pakistan's allies, especially the United States, have urged the government for years to eliminate Taliban strongholds in North Waziristan, a remote and mountainous region that borders Afghanistan.
The military launched its air operation on June 15, after months of peace talks between the government and the militants had made little progress. The government of Prime Minister Nawaz Sharif had been eager to strike a peace deal with the militants.
But during the sporadic talks, the Taliban launched several attacks, including an assault on Karachi airport that left 34 people dead.
The army then ordered the entire civilian population of North Waziristan to evacuate. More than 450,000 people left their homes.
Since the air operation began, 376 militants have been killed and 19 have surrendered, the military said. It said many of those killed were ethnic Uzbeks or Chinese Uighurs.
Seventeen soldiers had been killed.
The extent of civilian casualties is unclear. North Waziristan has been completely sealed to outsiders and there is no way to verify the military's death tolls.
Some men stayed behind to care for their homes and livestock because they could not afford to pay for transport out of the region.
Mohammad Yasin, a resident of Qutabkhel village in Miranshah, is one of the few that stayed. He said that Monday was the first time he had seen ground troops leave their heavily guarded base since the operation began.
"Before leaving the army camp, the security forces targeted adjoining villages and Miranshah bazaar through artillery and tanks and then two helicopters were seen shelling the same area where the troops later conducted house-to-house searches," he said. (Additional reporting by Katharine Houreld in Islamabad and Asim Tanveer in Multan; Editing by Nick Macfie)