ISLAMABAD, Pakistan — At least 18 people were killed in a missile strike in northwest Pakistan yesterday, according to witnesses and officials.

The missiles struck a house in the village of Shahnawaz Kot near the town of Wana in South Waziristan, a restive tribal region known as a refuge for pro-Taliban and Al Qaeda fighters. Local residents said they heard the sound of a warplane overhead, then three successive explosions. The strike, which demolished the house, also left several people wounded.

“When I heard the explosions, I rushed to the place where it happened. I saw dead bodies scattered everywhere,” Aziz Ullah Wazir, a village resident, said. “There were scores of people surrounding the collapsed building.”

Local residents said the home that was struck belonged to a man named Noorullah Wazir, whom they described as a Taliban supporter. Over the last year, villagers said, Mr. Wazir had allowed into his house several Arab visitors who were believed to have ties to guerrillas in the area.

Pakistani military officials confirmed yesterday that explosions were heard in the village and that several people had been injured, but said it was unclear what caused the blasts. An army spokesman, Brigadier Muhammad Tariq Jilani, said there were no Pakistani troops operating in the area at the time.

“There are not a lot of details available right now. We are looking into it,” Brigadier Jilani said. The American military during the last year has launched missile strikes against targets inside Pakistan’s borders. In January, a missile fired by an unmanned American drone in North Waziristan killed several suspected guerrillas, including a top Al Qaeda leader Abu Laith al-Libi.