MUSCAT: At least six workers were killed and others missing after rockslides engulfed a quarry in northern Oman on Sunday, emergency authorities said. Further slides in the wake of the deadly collapse were hampering rescue efforts at the quarry in Ibri, Al-Dhahirah governorate, the Gulf state’s Civil Defence and Ambulance Authority said.

Footage posted by the CDAA showed a towering cliff face crumbling onto the quarry below, creating a huge cloud of dust as workers shouted below. “The rockslides are still going on and hampering the search for missing people,” it tweeted.

“So far, six dead people have been recovered and four others have been treated in moderate to critical condition,” it said, without giving the victims’ nationalities.