The fire began Tuesday at the isolated Amur Gas Chemical Complex, a joint Russian-Chinese Venture in Russia's far-eastern Amur region.

"The rescue-search works have concluded. The deaths of 15 people -- including one Russian citizen and 14 foreign citizens -- have been confirmed," the company operating the site, Amur GKhK, said on social media.

It said all the dead were employees of a contracting company and that 39 people were still being treated for their wounds.

On Wednesday, the company said most of the victims were Chinese citizens.

Amur GKhK is jointly owned by Russia's Sibur and China's Petroleum and Chemical Corporation (Sinopec).