Swedish doctors and survival experts were calling it the "case of a lifetime" yesterday after an emaciated and near-speechless 44-year-old man was dragged from an icebound car, claiming he had been inside the vehicle for two months.

The man, identified as Peter Skyllberg, was discovered on Friday by a group of snowmobile drivers. They spotted his snow-covered car parked at the end of a track in a forest near the town of Umea, about 260km north of Stockholm in Sweden's frozen north, where temperatures hit -30C.

After brushing off a 2ft-thick crust of snow covering the vehicle, they were shocked to see a man curled up in a ball on the back seat, wrapped in a sleeping bag. Photographs of the inside of the car published yesterday showed the dashboard and driving seat coated with frost and ice.

Ebbe Nyberg, one of a team of policemen called to the scene, said: "He was in a very poor state. He said he had been there for a very long time and survived on a little snow."

Police said they believed his account.

An ambulance was called to the scene. Looking weak, pale, emaciated and scarcely able to speak, Mr Skyllberg was taken out of the back of the car and transported to the Noorland University hospital in Umea. He told astounded doctors that he had been snowed up inside the car since 19 December. Their patient was reported to be making a slow, but steady, recovery yesterday. Doctors said a healthy person who was sufficiently warm would normally expect to survive without food for a maximum of four weeks.

"But this is the case of a lifetime," Dr Ulf Segerberg, chief medical officer at Noorland hospital, said.

"Starvation for one month, anyone can tolerate that if they have water to drink. If you have body fat, you will survive even longer, although you end up looking like someone coming from a concentration camp."

Photographs from inside the vehicle appeared to show food and drinks wrappers, indicating he may have had some supplies in the car.

Dr Segerberg estimated Mr Skyllberg had lost between 15 and 20kg during his ordeal. Police and medical authorities offered different explanations for his survival. Dr Segerberg said he believed the snow covering the car had acted like an igloo and had kept the inside temperature sufficiently warm. However, Dr Stefan Branth, a doctor an Uppsala University, said he believed his metabolism may slowed down "like a bear that hibernates".

There was no immediate explanation as to why Mr Skyllberg's disappearance hadn't been reported by friends or relatives.

Sweden's Aftonbladet newspaper said that Mr Skyllberg had been struggling to pay off debts of about 1.6m Krona (£150,000) and a court had ruled that his rented home should be confiscated.