A planned exchange of Russian and Ukrainian prisoners of war failed to take place on Saturday, with Moscow accusing Kyiv of postponing the swap at the last minute, something Ukrainian officials dismissed as “dirty games” from the Kremlin.

Russia and Ukraine wrangled over details of a large prisoner swap, with officials in Kyiv rejecting claims by a Russian negotiator that they were dragging their feet on the planned exchange.

Kharkiv, one of Ukraine's largest cities, sits close to the Russian border and has been under frequent Russian shelling for more than three years.