BANGKOK -- Six foreign nationals were found dead at a hotel in downtown Bangkok on Tuesday, police said, dismissing earlier reports that they were killed following a shooting.

Metropolitan Police Bureau commissioner Thiti Saengsawang said the deceased bodies of three men and three women were found in a single hotel room and the cause of the deaths has not been confirmed.

He said initial investigations suggest that the incident may have been linked to poisoning, as suspicious substances were discovered in the hotel room and no signs of struggle were found at the scene.

Thai Prime Minister Srettha Thavisin ordered an investigation into the incident to prevent any impact on the public.