Ukraine's acting president has relaunched military operations against pro-Russian militants in the east after two men, one a local politician, were found "tortured to death".

Olexander Turchynov said the politician, named as Volodymyr Rybak, was found near rebel-held Sloviansk.

He disappeared soon after he was filmed trying to gain access to Horlivka city council, which had been seized by pro-Russian activists.

Daniel Sandford reports from Donetsk.