Updated

Investigators in the United Arab Emirates are looking into what caused a hot-air balloon to abruptly drop from the sky, injuring six tourists onboard.

Police in the emirate of Sharjah said Monday that the balloon struck the ground Saturday morning as it flew over the desert near the small town of al-Madam.

Police say the six European and Asian tourists suffered moderate to serious injuries and were being treated in a hospital. The nationalities of the victims were not released.

Sharjah is one of seven sheikhdoms in the UAE federation, anchored by a city of the same name immediately adjacent to Dubai.

Several people sustained minor injuries when another hot-air balloon crashed in the desert outside Dubai last February.