President Vladimir Putin ordered Sunday Russia's nuclear forces onto high alert in response to what he called "unfriendly" steps by the West. Russia has the world's largest arsenal of nuclear weapons and a huge cache of ballistic missiles.
The United States, the world's second largest nuclear power, slammed Putin's order as "totally unacceptable."
Germany said Putin's nuclear order was because his offensive into Ukraine had "halted" and was not going to plan.
The United States and European Union said they would exclude some Russian banks from the international bank payments system SWIFT and personally targeted Putin and Foreign Minister Sergei Lavrov. They also banned all transactions with Russia's Central Bank.
Russia's ruble plunged nearly 30% against the dollar Monday after world powers imposed fresh, harsher sanctions on Moscow over its invasion of Ukraine.
Russia’s Central Bank has amassed some $643 billion in international reserves in recent years, largely through sales of oil and gas. The cash pile — the world’s fourth largest — was supposed to be Russia’s insurance policy in the event of Western sanctions.
Travel, media sanctions
The EU on Sunday closed its airspace to Russian aircraft and banning Russian state media outlets broadcasting in the bloc.
The airspace ban would prohibit flights into or over the EU by "every Russian plane — and that includes the private jets of oligarchs,” said EU chief Ursula von der Leyen.
The move against Russian state media targeted its outlets Russia Today — known as RT — and Sputnik, and their subsidiaries.
Google, YouTube and Facebook banned Russian state media from monetizing content on their platforms.
Russia on Sunday detained at least 2,114 anti-war protesters across the country following thousands of arrests last week, an independent monitor said.
OVD-Info said anti-war protesters came out in 45 cities across Russia on Sunday.
Hundreds of thousands of people took to the streets worldwide Sunday denouncing Russia’s invasion of its neighbor.
Russia's army admitted Sunday that there were "killed and injured" soldiers among its troops in Ukraine on the fourth day of its invasion, without saying how many had died there.
Fighting in Ukraine has claimed dozens of civilian lives, forced hundreds of thousands to flee their homes and turned Russia into a global pariah.
Ukraine said it had agreed to send a delegation to meet Russian representatives at the border with Belarus, which has allowed Russian troops passage to attack Ukraine, insisting there were no pre-conditions to the talks.
AFP contributed reporting.