Russia says the liberation of eastern Ukraine's Donbas region is an unconditional priority for Russia.

In an interview, Russian Foreign Minister Sergei Lavrov said it is, however up to the rest of Ukraine if people there are happy to return to the authority of a neo-Nazi regime that has proven it is Russophobic in essence.

Meanwhile, Ukraine's President Volodymyr Zelensky has visited troops in the Kharkiv region, on the country's battered eastern front line.

In another development, Serbia’s President Aleksandar Vucic has announced that he has secured an extremely favourable three-year natural gas supply deal with Russia.