A gunman opened fire at Bangkok’s Or Tor Kor Market, resulting in six deaths, including his own. The incident has raised urgent calls for gun control reforms in Thailand and is being investigated for potential links to recent border conflicts with Cambodia.

A gunman killed four security guards and wounded one other person in a mass shooting at a popular fresh food market in Thailand’s capital on Monday, police said. “Police are investigating the motive. So far it’s a mass shooting,” said Worapat Sukthai, deputy police chief of Bangkok’s Bang Sue district where the incident took place.