Two buses collided head-on and fell into a ditch in northern India, killing at least eighteen people and injuring more than two dozen others, police said on Sunday. The cause of the accident was not immediately known.

The accident happened on a narrow road in the Chiluataal area of Uttar Pradesh (UP) state, about 15 kilometers (9.3 miles) from the city of Gorakhpur, when a private bus and a UP State Road Transport Corporation (UPSRTC) bus collided head-on. The buses then fell partly in a ditch next to the road, witnesses said.

"Eighteen people have died in this accident," a local police officer said, adding that they were identified as thirteen men, three women and two children. A total of 26 people were injured in the accident, including more than a dozen people who were said to be in a serious or critical condition.

The cause of the accident was not immediately known, but local officials said the collision happened when the overloaded private bus tried to avoid a three-wheeler which was ahead of it. When the private bus made the sharp turn, the UPSRTC slammed into the vehicle.

India, the world's second most populous nation, is often the scene of deadly road accidents, many of which are attributed to reckless driving, aging vehicles and overloading. In new figures released in 2010, India overtook China to top the world in road fatalities.

According to India's National Crime Records Bureau, approximately 120,000 people are killed in road accidents in India each year. Deaths as the result of road accidents account for up to 40 percent of the country's deaths due to unnatural causes.