Russia's upper house of parliament has unanimously approved a treaty on annexing Ukraine's Crimea region, clearing the way for President Vladimir Putin to sign it into law.
Crimea's leaders and Mr Putin signed a treaty making the region part of the Russian Federation on Tuesday. A referendum in Crimea last Sunday, approving its split from Ukraine, came after Crimea was taken over by pro-Russian forces in February.
Mr Putin is expected to complete the ratification process by signing the treaty at a ceremony with the speakers of both chambers on Friday.
Meanwhile, the European Union has stepped up sanctions against Russia following the annexation of Crimea, just hours after the United States announced its measures.
EU leaders meeting in Brussels added a dozen more names to a list of Russian and Crimean officials who will be subject to visa bans and asset freezes.
The EU's executive was also asked to prepare for broader economic sanctions, if the Ukraine crisis escalates, the BBC reports.
European Council president Herman van Rompuy declared that the EU would not recognise the annexation of Crimea now or in the future and the next summit between Russia and the EU planned for June has been cancelled.
The European Commission said it would be drawing up a list of further sanctions which could be implemented if Russia escalates its actions in Ukraine.
German Chancellor Angela Merkel told a news conference that there had been an unbelievable loss of trust with Russia and raised the prospect of sending an EU mission to Ukraine.
US targets Putin's close allies
In the United States, President Barack Obama announced further sanctions against Russia, targeting 20 individuals closely associated with President Putin, as well as a bank controlled by his allies.
Any assets the individuals have in America will be frozen and they will also be barred from US travel, Reuters reports.
Mr Obama is also threatening broader penalties against key sectors of Russia's economy if Moscow moves further into Ukraine. Senior administration officials say that could include the energy, defence and financial services sectors.
Shortly after President Obama's announcement, Russia said it was imposing its own sanctions against US officials and politicians.
Among the nine individuals barred from Russia under the sanctions are senior Congressmen Harry Reid, John Boehner and John McCain as well as one of Mr Obama's national security advisers.
In a separate development in Crimea, pro-Russian armed men are said to have seized a Ukrainian military ship anchored in the Crimean port of Sevastopol. A Ukrainian defence ministry spokesperson says at least 15 men stormed the vessel and set off stun grenades.