Retired rocket scientist Anatoly Alexandrovich has a blunt suggestion for how the Russian healthcare system could be improved: "Drop an atomic bomb on it."

The Kremlin on Wednesday denied involvement in air strikes on Syria's rebel-held Eastern Ghouta enclave that monitors say have killed at least 250 civilians since the start of the week.

"These are groundless accusations. It is not clear what they are based on. No specific data has been given. We do not agree (with them)," said presidential spokesman Dmitry Peskov in response to a U.S. briefing saying that Russia was responsible for the attacks.

The United States has urged Russia to use its leverage over Syrian President Bashar al-Assad to end the war as the U.N. envoy warned of a "worrying and dangerous" moment in the nearly seven-year conflict.

Russia on Friday marked 75 years since the Soviet Union's victory in the major World War II Battle of Stalingrad, extolled as a symbol of the country's resilience as President Vladimir Putin campaigns for his fourth term.

Russian President Vladimir Putin on Thursday called an explosion that tore through a Saint Petersburg supermarket, wounding 13 people, "an act of terror." 

Five people were killed when a city bus plowed into a pedestrian underpass in western Moscow on Monday, traffic police said.

Russia's presidential election will take place on March 18, the upper house of parliament said Friday, in polls that are all but certain to return Vladimir Putin to the Kremlin for a new six-year term.

Russian authorities were reluctant to celebrate the 100th anniversary of the 1917 Bolshevik Revolution on Tuesday, with just low-key events being held to mark an uprising that launched more than 70 years of Communist rule. 

Saudi Arabia signed on Thursday preliminary agreements to buy S-400 air defense systems and receive "cutting edge technologies" from Russia during King Salman's landmark visit to Moscow, the Saudi military industries firm said.

The agreement was announced as King Salman, who is on the first official trip to Russia by a Saudi monarch, and Russian President Vladimir Putin held talks at the Kremlin.

Saudi Arabia's King Salman, on a landmark visit to Russia, and President Vladimir Putin on Thursday signed a slew of arms and energy deals as the key U.S. ally seeks to deepen cooperation with Moscow.