Moscow has completed the process of making Ukraine's Crimea part of Russia, as Ukraine's prime minister, in a highly symbolic move, signed a political cooperation agreement with the European Union.
And the European Union has released the names of 12 more Russians and Ukrainians who are being hit with sanctions to punish Russia over the Crimea annexation.
President Vladimir Putin signed laws on the incorporation of Crimea into the Russian Federation on March 21 after the upper house ratified the annexation treaty earlier in the day. The State Duma, the lower house of parliament, overwhelmingly backed the treaty in a session the previous day.
Ukraine has said it will continue to fight for Crimea's "liberation."
Many states have rejected the annexation as a clear violation of international law, and the United States and the European Union have imposed two rounds of targeted sanctions over the move.
EU President Herman Van Rompuy said the signing early on March 21 of political chapters of the Association Agreement with Ukraine showed how important the relationship between the two sides is.
"Today, we are signing the [association] agreement's political provisions," Van Rompuy said. "It shows our steadfast support for the course the people of Ukraine have courageously pursued. Today is but the opening act. We expect to soon sign the agreement's remaining parts, not least the economic provisions. Together with the political ones, they form a single instrument."
Van Rompuy and other EU leaders signed the agreement with Ukraine's Prime Minister Arseniy Yatsenyuk on the sidelines of an EU summit in Brussels. The two sides signed three of the seven chapters of the agreement.
"This deal covers the most existential and most important issues, mainly security and defense cooperation," Yatsenyuk said. "This deal will establish a joint decision-making body, which is to facilitate the process of real reforms in my country. And this deal meets the aspirations of millions of Ukrainians that want to be a part of the European Union."
It was the refusal by ousted President Viktor Yanukovych to sign association and free-trade agreements with the EU in November 2013 that triggered months of crisis.
On the first day of the EU summit on March 20, EU leaders warned against any steps by Russia to further destabilize the situation in Ukraine.
Both the United States and the European Union also expanded their respective sanctions lists. The United States imposed sanctions on allies of President Vladimir Putin, as well as Bank Rossiya, which has close ties to the Russian leadership.
In retaliation, the Russian Foreign Ministry banned nine U.S. lawmakers and officials from traveling to Russia.
With its 12 additions, the EU has now imposed sanctions on more than 30 Russians and Ukrainians in the past week.
The new names on the list include Putin advisers Sergei Glazyev and Vladislav Surkov, Federation Council Chairwoman Valentina Matviyenko, and Sergei Naryshkin, the State Duma lower house.
Dmitry Kiselyov, the TV journalist who warned the United States could be turned "into radioactive ash" is also on the list, as well as Igor Turchenyuk, who the EU says is "the de-facto commander of Russian troops deployed on the ground in Crimea.
Putin on March 21 said there was no need for Russia to further retaliate against U.S. sanctions.
In televised comments, the Russian president also quipped that he would open an account with Bank Rossiya.
Foreign Minister Sergei Lavrov, speaking to the Federation Council ahead of the vote, said Western sanctions against Russian officials were irrational and would create unnecessary barriers.
The Federation Council in a statement denounced the sanctions as "political blackmail."
United Nations Secretary-General Ban Ki-moon, on a visit to Kyiv on March 21, urged respect for Ukraine's sovereignty.
Ban was speaking after talks with acting Ukrainian President Oleksandr Turchynov, who said Ukraine will never accept Russia's seizure of Crimea.
With reporting by Reuters, AP, and AFP