Close Kyiv stages one of deadliest strikes since invasion began 600 miles inside RussiaOn The Ground newsletter: Get a weekly dispatch from our international correspondents Get a weekly dispatch from our international correspondents Get a weekly international news dispatch Email * SIGN UP I would like to be emailed about offers, events and updates from The Independent. Read our Privacy noticeA Ukrainian drone attack has hit 600 miles deep inside Russia on Monday, according to local authorities. Ukraine’s military confirmed the attack on the refinery but is yet to comment on the reported strikes in Nizhnekamsk. At least 13 people have been killed in the attack including one child with over 75 injured, according to Russian authorities. It comes as Ukraine's Volodymyr Zelensky claimed North Korea was preparing to deploy as many as 50,000 soldiers to support Russia's war effort.