Five students from a medical college were found dead Monday morning in a rented house in Beijing, probably due to carbon monoxide poisoning, police said.

Arriving at the rented house in Chaoyang District at around 8:30 am, emergency doctors found the five men, from Harbin Medical University in northeast China's Heilongjiang Province, had all stopped breathing and had no pulse, police said.

The students were immediately rushed to a nearby hospital for treatment. But they died despite doctors' efforts.

They had been working as interns at the China-Japan Friendship Hospital in Beijing, according to the police. Six people were living in the house, but one of them had not been present on the night the tragedy occurred.

Initial investigation showed the five were killed by carbon monoxide, although the exact cause of their deaths is still being investigated.