ISLAMABAD (AP) — A gas cylinder explosion early Sunday after a wedding reception at a home in Pakistan’s capital killed at least eight people, including the bride and groom, police and officials said.

The blast occurred as guests who had gathered to celebrate the couple were sleeping at the house, causing part of the house to collapse, according to the Islamabad police. Seven people were injured.

In a statement, police said the explosion occurred in a residential area in the heart of the city. A government administrator, Sahibzada Yousaf, said authorities were alerted about the blast early Sunday and officers are still investigating. He said some nearby homes were also damaged.

Prime Minister Shehbaz Sharif expressed grief over the loss of lives and offered condolences to the victims’ families, according to a statement from his office. He directed health authorities to ensure the injured receive the best possible treatment and ordered a full investigation.

Many Pakistani households rely on liquefied petroleum gas cylinders because of low natural gas pressure, and such cylinders have been linked to deadly accidents caused by gas leaks. Police said investigations were ongoing.