Bangkok, Thailand (CNN) -- An explosion killed at least two people Monday in a city in southern Thailand, a police official who is familiar with the investigation said.
The blast occurred around 6 p.m. (6 a.m. ET) in a market in Muang District, which is the main city of Narathiwat Province, said the police official, who declined to be named because he is not authorized to speak to the news media.
The explosion happened at the market's busiest time of the day.
Initial reports indicate two people were killed and nine hurt, the official said.
The explosion happened as Malaysia's prime minister is to begin a three-day trip to southern Thailand, where a Muslim insurgency has caused violence for years.
The Narathiwat province is one of three Muslim provinces in southern Thailand, a predominantly Buddhist country.