Rohtak (Haryana), May 6 (IANS): At least 20 people were injured when eight coaches of the Punjab Mail derailed in Sampla area of Haryana's Rohtak district early Sunday.

The derailment occurred around 4 am., railway officials said. None of the passengers had serious injuries.

The injured were admitted to the Postgraduate Institute of Medical Sciences (PGIMS) at Rohtak, 70 km from New Delhi.

The train was going from Ferozepur in Punjab to Mumbai. Traffic on the Rohtak-Delhi section was affected.

Railway officials said five of the derailed coaches had overturned after derailment. The derailed coaches included six bogies of the second-class sleeper (S-5 to S-10), one luggage compartment and the guard coach.

"Most of the passengers in the derailed coaches were sleeping when the accident took place," said police officials at the spot.

They said that at least 50 metres of the railway track were found broken at the accident site.

"We are trying to ascertain whether the railway track broke due to the accident or whether the broken track led to the accident," one railway official at the accident site said.

Railway officials have ordered a probe into the accident. Efforts were being made to clear the track and restore traffic later during the day.