An explosion from a gas cylinder killed at least eight people, including the bride and groom, at a home in Islamabad early Sunday after a wedding reception, police and officials said. Seven others were injured, and part of the house collapsed, Islamabad police said.

Police said the blast occurred in a residential area in the heart of the city, where guests who had gathered for the celebration were sleeping at the house. Officers were investigating the cause of the explosion, with reports saying authorities were alerted early Sunday.

Sahibzada Yousaf, a government administrator, said the blast was reported early Sunday and that officers were still investigating. Yousaf also said some nearby homes were 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. The statement said Sharif 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 as investigations continued.