Fifty people were injured on Saturday when the engine on a Bangkok commuter boat exploded, pitching several passengers into one of the city’s canals, emergency officials said.

The boat was ferrying

passengers on a major waterway in the eastern outskirts of the city, which boasts an extensive network of canals teeming with motorised commuter boats during rush hour.

“As of now, we have 50 injured and sent to five hospitals, of these two are in critical condition,” an official at the interior ministry’s disaster centre said.

The city’s Erawan emergency medical centre also confirmed that at least 50 were hurt in the accident, although the nature and severity of the injuries was not immediately clear.

Images provided by police showed that the boat was rattled by the explosion but still largely intact.

Local police commander Sarayuth Junnawat said the explosion was believed to have been caused by a fuel leak onboard.

The boat was travelling on the Saen Saeb canal, which runs through the heart of the capital city and eventually connects to its main river Chao Praya.