Armed police are patrolling a cemetery in a far eastern Russian city and escorting mourners after two bears strayed from the woods in search of food.

The two Asiatic black bears were spotted in the cemetery in a suburb of the industrial city of Komsomolsk-on-Amur on Wednesday, city police said in a warning posted on their website on Thursday.

The two bears entered the cemetery from nearby woodland. The police officers fired warning shots, after which the bears returned to the forest.

"The police of Komsomolsk-on-Amur ask members of the public to refrain from visiting the city cemetery," they warned, saying five officers were patrolling the site and escorting funeral processions.

Russians traditionally place food beside graves of relatives, which may attract bears.

The cemetery's staff have denied speculation in local media that the bears could dig bodies out of coffins.

Komsomolsk-on-Amur, a city known for building fighter jets, has a population of around 255,000 people. It is around 6,000 kilometres (3,700 miles) north east of Moscow.

Bears have recently stepped up their forays into cities in far eastern Russia due to a lack of food in forests and delayed fish spawning, RIA Novosti state news agency reported. The delay in spawning is believed to be linked to climate change.

Asiatic black bears, which have a distinctive white V on their chests, are found in Iran, Afghanistan, India, Pakistan, China and Japan as well as Russia's far east.

WWF says the bears are suffering from a loss of habitat caused by logging, road building and expanding human settlements, as well as poaching of the animals for body parts, which are used in Chinese traditional medicine and also considered a culinary delicacy in the country.

In Russia, bear hunting is permitted despite calls from conservationists to ban the practise.