Two light rail trains collided in a tunnel in Kuala Lumpur, Malaysia, injuring more than 200 people, in the first major crash for the 23-year-old metro system.

Pictures on social media after the Monday night collision showed bloodied passengers, some lying on the floor of the carriage strewn with blood and shattered glass.

Transport minister Wee Ka Siong told local media that a metro train carrying 213 passengers collided with a vacant carriage on a test-run in a tunnel near the Petronas Towers, one of the world’s tallest twin towers.

“One carriage was travelling at 20kmph (12.4 mph) and another at around 40kmph (24.8 mph) when the collision happened. This caused a significant jolt that threw some passengers out of their seats,” he was quoted as saying.

Federal territory minister Annuar Musa tweeted on Tuesday that three passengers were in critical condition and have been intubated. More than 40 had serious injuries.

Prime Minister Muhyiddin Yassin pledged a full investigation into the cause. Police said they suspected a miscommunication from the trains’ operation control centre. The vacant carriage had a driver while the train with passengers was a fully-automated and controlled by the operation centre.