The Foreign Office is looking into reports that four have died in a nightclub in Thailand that is popular with British tourists.
They were killed when a fire swept through the Tiger Disco club on the Thai resort island of Phuket.
Police colonel Jirapat Phothanaphan said the nationalities of the dead were not yet known, but both Thais and foreigners were among 11 people injured.
Mr Jirapat said the fire broke out about two hours before dawn at the club, which is on a main entertainment street in Phuket's popular Patong beach area.
He said the cause of the blaze was not yet known, but authorities suspected heavy rain that led to sparks at a nearby electricity transformer may have triggered it.
The BBC reported that up to 20 people may have been injured, and that some were seriously burned.
A BBC reporter in Thailand said local police suggested lightning may have struck an electricity transformer, causing the blaze.
A spokeswoman for the Foreign Office confirmed it was aware of the incident and is investigating whether any British people were involved.