Russian opposition leader Boris Nemtsov was shot dead in central Moscow late ahead of a major opposition rally this weekend, investigators and police said.
Estonia's centre-left coalition is poised to return to power in an election marked by nerves in the NATO member over the military resurgence of Russia.
US Secretary of State John Kerry will meet next week with his Russian and Iranian counterparts seeking an end to fighting in Ukraine and to advance a nuclear deal with Iran.
Russia called Western threats of fresh sanctions against Moscow evidence that Washington and Brussels are not interested in the success of a troubled truce in Ukraine.
Russia will continue using the International Space Station along with NASA until 2024, its space agency said, after Moscow had threatened to stop financing it in 2020.
The Ambassador of Kazakhstan to Belarus and Belorussian Foreign Minister met to discuss a possibility of talks between presidents of Kazakhstan, Russia and Belarus.
Estonia marked its independence day with a military parade featuring NATO hardware and troops on its eastern border with Russia amid heightened east-west tensions over Ukraine.
Russia voiced confidence that world powers and Iran would be able to reach a comprehensive accord over Tehran's disputed nuclear programme by a June 30 final deadline.
Moody's cut Russia's debt rating by one notch into 'junk' territory, saying the Ukraine crisis and the fall in oil prices and the ruble will further undermine Russia's economy.
Pussy Riot, the Russian band jailed after mocking the Kremlin, has released a first English-language song that takes aim not at Vladimir Putin but at US police brutality.