Russia on Friday threw its weight behind Belarus's increasingly isolated regime, slamming a European overflight ban as President Vladimir Putin prepared to host strongman Alexander Lukashenko.

Russia's FSB security service said on Saturday it had detained a Ukrainian diplomat, accusing him of receiving sensitive information from a Russian national.

A team of doctors successfully completed open heart surgery inside a Russian hospital that caught fire on Friday as firefighters battled the flames from the outside, regional emergency services said.

Russia has registered the world's first vaccine against Covid-19 for animals, the country's agriculture safety watchdog Rosselkhoznadzor said on Wednesday.

Kremlin critic Alexei Navalny lost his appeal on Saturday against what he said was a politically motivated decision to jail him for nearly three years, but said his faith in God and belief in the rightness of his cause was sustaining him.

A Pakistani lab will soon receive Russia's Sputnik V Covid-19 vaccine for commercial sale, a company official said on Sunday, making Pakistan one of the first countries to market shots privately as it scrambles to secure supplies.

Russian police detained dozens of protesters on Saturday as supporters of jailed Kremlin critic Alexei Navalny took to the streets following his call to protest against President Vladimir Putin's rule.

Three people were killed Friday in a gas explosion at a mine in the Russian region of Siberia, prosecutors said.

Before he returned to Russia, opposition politician Alexei Navalny and his supporters had anticipated he would be arrested and planned to force the Kremlin to release him by staging repeated protests, a close ally has said.

Kremlin critic Alexei Navalny took off on a plane bound for Russia on Sunday, to return home for the first time since he was poisoned last summer, despite Russian authorities' stated desire to arrest him and potentially jail him for years.

South Korea said on Tuesday it had scrambled fighter jets in response to an intrusion into South Korea's air defence identification zone by 19 Russian and Chinese military aircraft.

Donald Trump's outgoing administration is planning to close the two remaining US consulates in Russia, the State Department confirmed Saturday, as President-elect Joe Biden prepares to take office amid high tensions with Moscow.