Nineteen people were injured when a metrobus, Istanbul's famous single-lane mass transit bus, hit another metrobus early Sunday in the Yenibosna district.

Two people were in critical condition after the accident that caused delays in metrobus services.

Investigations are underway on the cause of the accident that left one of the buses with all windows broken.

In June, two metrobuses collided head-on in Istanbul's Asian side and 29 people were injured.