Four Japanese tourists were killed Wednesday in a car accident in Ayutthaya, central Thailand, local police said.

The Japanese Embassy in Bangkok confirmed the death of the four -- two men and two women. Local media reported that a Thai tour guide also died in the accident, while the driver was seriously injured.

(Thailand emergency authorities)

The accident occurred in Ayutthaya, about 80 kilometers north of Bangkok, at around 4 p.m. when the car carrying the four appears to have crashed into a slow-moving truck and burst into flames, according to media reports.

The car was apparently traveling at over 100 kilometers per hour at the time. Given the circumstances, the police are looking into the possibility that the driver may have dozed off at the wheel, according to the reports.

The four were identified as Katsuhiko Narimoto, 65, Haruka Narimoto, 30, Kumiko Komeima, 59, and Yoshio Komeima, 68. They were on a sightseeing tour organized by Tokyo-based Nippon Travel Agency Co.

The four left Kansai airport in Osaka Prefecture on Tuesday and were due to return to Japan on Friday after touring Bangkok and Ayutthaya. They were making a one-day trip to the popular tourist spot when they were killed in the accident, according to the travel agency.

"We would like to express our deepest condolences to the families of the deceased," agency President Akihiro Horisaka said at a news conference in Tokyo.