At least six people all of Vietnamese origin have been found dead in their luxury hotel room in Thailand’s capital, Bangkok, police say.

Some of the dead were Vietnamese-American, according to the government.

Local media initially suggested there had been a shooting at the five-star Grand Hyatt Erawan Bangkok, but police dismissed these reports and said there was no evidence of gunfire.

Local media are now reporting that police believe the victims may have been poisoned, however this has not been confirmed and the deaths remain unexplained.

Thailand’s Prime Minister, Srettha Thavisin – who visited the scene – has ordered an investigation into the deaths, saying he does not want the case to affect the country’s image or have an impact on tourism.

He said police suspected the deceased had been dead for 24 hours and post mortem, examinations would be carried out to determine if it was something they had eaten.

Police suspected there may be a seventh Vietnamese but that individual has not been found, he added.

Earlier, the Thai Public Broadcasting Service quoted police saying that three women and three men had died.

Police Major General Thiradech Thamsuthee told the broadcaster that an initial investigation suggested the victims had been poisoned.

“There were no signs of struggle. Tea and coffee cups were found to have been used,” PBS reported.

Police were called to the hotel at around 17:30 local time after receiving a phone call from hotel staff.