SOFIA, BULGARIA: Four people were confirmed dead in northeastern Bulgaria following a gas explosion on a derailed train early Saturday, firefighters in Bulgaria said. At least 23 people were injured.

Nikolay Nikolov, who heads the country's firefighting department, said at least 20 buildings in the village of Hitrino were destroyed when containers of liquefied petroleum gas exploded at 5:40 am local time (0340 GMT).

The immediate surroundings of the disaster site were evacuated, and the cause of the disaster was unclear, Nikolov said.

Video footage from the scene showed many houses in the village of 800 on fire and ambulances taking the injured to hospitals.

Prime Minister Boiko Borisov was traveling to the village, the government announced. He urged citizens to donate blood to address shortages at the nearby hospitals.

(Updated at 3:10 pm)