A man cleans broken glass next to a building hit by shelling, what local authorities called a Ukrainian military strike, in the course of the Russia-Ukraine conflict in Belgorod, Russia, May 9. Reuters-Yonhap

Ukraine's SBU security service carried out a record distance drone strike on a Russian refinery located nearly 1,200 kilometres (746 miles) from the border, a Ukrainian defence source said Thursday.

The source told AFP the strike on the refinery in the Russian republic of Bashkortostan was "the SBU's work" and was carried out at a "record range." (AFP)