A gigantic truck bomb has destroyed the Marriott Hotel in Islamabad, Pakistan, killing at least 40 people including one member of the US military.

A massive truck bomb destroyed much of Islamabad’s most popular hotel this evening, killing at least 40 people, wounding at least 100 and leaving a crater more than 25 feet deep. Officials feared the death toll would increase by dozens as rescue teams continue work at the scene.

At approximately 8 p.m. local time, an apparent suicide bomber blew himself up as his vehicle was being checked at the security gate of the luxury Marriott Hotel. The bomb was felt as far as 15 miles away. Within 500 feet of the blast, buildings and trees were shredded by the bomb, which was believed to be the biggest in Islamabad’s history.

In the minutes after the blast, dozens of dead bodies littered what used to be the lobby of the hotel. Between the entrance and the security checkpoint, about 50 feet away, there were mounds of rubble under which more dead are feared to be buried.

At least one member of the U.S. miltary was missing at the scene of the blast and presumed dead. Other U.S. military members eating at the hotel’s restaurant sustained non-life-threatening injuries.