GAUHATI, India: Nine people were killed when a passenger bus traveling overnight in India’s remote northeast swerved over a bridge and broke through the railing to fall into a marshy ravine before dawn Sunday, police said.

Another 28 injured passengers, some in critical condition, were taken to a hospital.

Authorities were investigating what caused the crash around 2 a.m. near the town of Kaliabor in Assam state. Police in the state capital of Gauhati said the driver was among those killed.

TV news channels broadcast images of the overturned bus lying upside down in the swamp about 6 meters (20 feet) below the bridge. Nine bodies covered with white sheets were lined up along the road.

The bus was carrying 35 people, below its capacity of 40, when it departed Saturday evening from the north Assam town of Lakhimpur on an overnight journey to Gauhati.