PHUKET: At least three people were reported killed and others trapped in the rubble of an office building under construction that collapsed on Thursday afternoon.

The office block, being built for a petrol company, collapsed around 1pm. An excavator was being used to clear away a large slab of concrete and rubble so rescuers could get to workers trapped beneath it.

The new building, owned by Sai Si Nam-ngern Co, is located near a HomePro hardware store.

Deputy Phuket governor Wongsakorn Noonchukhan said the cement floor on the second storey of the office block fell onto the ground at around 12.50pm. The cause of the collapse was not yet clear, he added.

Sompong Pinpakdee, director of the Phuket disaster prevention and mitigation office, said three workers, including two Thais and one Myanmar man, were killed. They were Jeerachai Wonghasak, 35, Ms Pronpimol Waewong, 21, and an unidentified Myanmar man.

The number of workers who went missing was not yet known, said Mr Sompong. Only three of them — all Myanmar nationals — were identified.

Pol Col Theerawat Liamsuwan, chief of Thalang police, said investigators would call a contractor and and an engineer responsible for construction for questioning.