The Kremlin on Thursday hailed as a "triumph" overwhelming backing in a national vote on constitutional reforms to extend President Vladimir Putin's rule.

Russians go to the polls Thursday to cast early votes in a nationwide ballot on constitutional reforms that could see President Vladimir Putin remain in power until 2036.

Early voting began in remote parts of Russia on Wednesday ahead of a referendum that could extend President Vladimir Putin's term in the Kremlin, despite coronavirus fears and rising infections. 

Prime Minister Mikhail Mishustin on Monday announced the first steps to allow Russia's citizens to travel beyond its borders after they closed to prevent the spread of the coronavirus.

Russia on Tuesday recorded its highest daily coronavirus death toll of 174 but said more than 12,000 people had also recovered over the past 24 hours.

Russian Prime Minister Mikhail Mishustin is returning to work after fighting off the coronavirus, the Kremlin said Tuesday.

President Vladimir Putin told Russians they are "invincible" when they stand together as the country on Saturday marked the 75th anniversary of the end of World War II on lockdown from the coronavirus.

Russia on Saturday reported its largest increase in coronavirus cases with the new infections rising by nearly 10,000 in a single day.

Coronavirus cases in Russia surged past 100,000 on Thursday, the government said, with an increase of 7,099 confirmed infections in the last 24 hours.

US President Donald Trump said Tuesday he was ready to help resolve an escalating oil price war between Russia and Saudi Arabia that has helped push crude benchmarks to 17-year lows.

The threat of a global recession triggered by the coronavirus pandemic had already hammered prices when Riyadh said last month it would raise exports after a production-cut agreement among top producers flopped in early March.