Six people have been found dead at a luxury hotel in central Bangkok, in what authorities say could be a case of poisoning, writes The Guardian.

The bodies of three women and three men were found inside a hotel suite on the fifth floor of the Grand Hyatt Erawan hotel by a hotel worker late on Tuesday afternoon.

They were Vietnamese, and two had American citizenship, the Thai prime minister, Srettha Thavisin, said.

It is assumed the six had been dead for at least 24 hours before their bodies were discovered, police said, adding that the room had been locked from the inside, but that the staff member was able to enter through a separate door.

The cause of death is not yet known. However, Srettha said there was no sign of robbery or an attack, adding the cause was “presumably something related to consumption which needs to be investigated”.