The United States and European Union have warned Moscow it faces more sanctions if Russian troops intervene further in Ukraine.
Here is a look at where things stand now.
EUROPE: The European Union has slapped visa bans and asset freezes on 33 Ukrainian and Russian officials and business leaders, including members of President Vladimir Putin's inner circle and Black Sea and Crimea commanders.
The list includes Russian Deputy Premier Dmitry Rogozin, Putin's aide Vladislav Surkov, and the speakers of both chambers of the Russian parliament.
EU leaders have joined counterparts in the Group of Seven (G7) most industrialised economies in cancelling a G8 summit scheduled with Russia in June.
Brussels has suspended talks with Moscow on a visa liberalisation scheme, and on a new overall EU-Russia cooperation accord.
UNITED STATES: Washington has announced visa bans and asset freezes against 27 people, including both Crimea's breakaway leaders and Russian politicians and businessmen.
Among them are Putin's chief of staff Sergei Ivanov. Businessmen Arkady and Boris Rotenberg and Yury Kovalchuk are considered members of the Russian leader's inner circle.
Customers of several Russian banks associated with the blacklisted individuals have been banned from using Visa and MasterCard credit cards.
The US has suspended military cooperation with Russia, and blocked exports of sensitive dual-use materials and technologies.
It is withholding licenses for sales of police and military gear and hardware, toxic chemicals and explosives detonators.
OTHERS: Canada has sanctioned seven Russian and three Crimean officials.
Japan has suspended talks with Russia on easing visa requirements and said it will not begin negotiations on a new investment accord.
The Organisation for Economic Cooperation and Development, the club of the world's most advanced economies, has suspended talks on Russian membership.
NATO has suspended military and civilian cooperation including its first joint mission with Russia, the maritime escort of a US ship tasked with neutralising Syria's chemical weapons.
EU leaders have warned of wider, undefined economic measures.
France, which has suspended most of its military cooperation with Russia, must decide whether to sell two Mistral-class helicopter assault ships, the first of which is due for delivery in October.
French officials have said that cancelling the 1.2 billion euro ($1.4 billion) contract could only happen as part of a broader package of EU sanctions against Russia.
Economic sanctions are a double-edged sword, likely to hurt all concerned.
Russia and the EU have common interests in the energy sector given that the 28-member bloc gets one quarter of its supplies from Russia.