The accident occurred at 8:45 p.m. local time when one of the trains, which was going on a test run and had only one driver, collided with a train carrying passengers.
Both trains, which are operated by Prasarana Malaysia Berhad, were traveling at 40 km (approximately 25 miles) per hour when they collided in a tunnel between the Kampung Baru and KLCC stations, state media said.
Some 166 people sustained minor injuries and were sent to nearby hospitals for treatment, including Kuala Lumpur Hospital. Forty-seven passengers were severely injured, state media added.
Videos and photos posted on social media showed several passengers bleeding and broken glass panels inside the trains.
Malaysia’s Prime Minister Tan Sri Muhyiddin Yassin has called for a full investigation to discover the cause of the accident.
“I take this accident seriously and have instructed the Transport Ministry and Prasarana Malaysia Berhad to conduct a full investigation,” he said, Bernama reported.
Transport Minister Wee Ka Siong said the collision was the first major accident in the metro system’s 23 years of operation, and he pledged a thorough investigation, Reuters reported.