DAMASCUS, Syria (AP) – A blast at a gas station in a Damascus suburb killed three people Thursday, gutting the back of an empty bus and blowing out nearby windows, officials said.

Syria’s interior minister, Said Mohammad Sammour, ruled out a terrorist attack.

Sammour said on state-run Syrian TV that the Iranian bus driver and two Syrian gas station workers were killed when a tire they were pumping air into exploded.

Witnesses reported seeing flames, but it was not immediately clear how the fire started.

The back of the bus, where the engine is located, was gutted and charred along with the rear seats. The worst damage appeared to be to the outside of the bus. The explosion also blew out the windows of a gas station office.

The blast happened in Sayyida Zainab, a Damascus suburb popular with Iranian and other Shiite pilgrims. It is the site of a shrine dedicated to the granddaughter of the Prophet Muhammad.

The bus was carrying pilgrims to the shrine, about a mile (2 kilometers) from the gas station, but nobody was on board at the time of the blast. Syrian TV quoted Sammour as saying “there were no explosives involved” and that there were no pilgrims nearby. Police sealed off the area and reporters were banned from reaching the site.