A Russian nuclear submarine reportedly caught fire in a shipyard in the north of the country on Tuesday.

News agencies say the vessel was undergoing repairs in Severodvinsk, in the province of Arkhangelsk.

There are no reports so far of any casualties.

The Interfax agency quotes a source as saying there were no weapons on board.

Also, the Tass agency says the nuclear reactor had been shut down prior to the blaze.

The 949 Antei Oscar-class submarine, named Orel, is the sister vessel of the Kursk, which sank after a fire and explosion in 2000.

Some reports say the fire began during some welding work and insulation material caught alight.

ФОТО: В Северодвинске горит подводная лодка http://t.co/4k0l0F3gaJpic.twitter.com/Z0rOwZu7rI — Срочный по Северу (@flashnord) abril 7, 2015