COLOMBO, Sri Lanka (AP) — Two trains have collided head-on in northwestern Sri Lanka, injuring 68 people.

Police spokesman Ajith Rohana says the crash took place Wednesday at the railroad station in Pothuhera, about 90 kilometers (56 miles) northeast of Colombo, Sri Lanka’s capital.

He says a train from Colombo traveling to Pallai in the north crashed into a southbound train that was stopped at the station. The cause of the crash is under investigation.

Rohana says four of the injured passengers are in serious condition.

Trains are a popular mode of transport in the island nation, and are generally considered safe.