US President Barack Obama said he is ramping up sanctions against Russia as European leaders began huddling in Brussels to discuss ways of punishing Moscow for its takeover of Crimea.
The escalating moves by the United States and EU came as Ukraine warned that Russia was not just seizing Crimea but also appeared to be preparing a large-scale assault on other parts of the country.
Russia's State Duma, or Lower House of Parliament, overwhelmingly approved a treaty annexing Crimea from Ukraine on Thursday.
Russia's Federation Council, or Upper House, is expected to vote on Friday, completing ratification of a treaty signed by Russian President Vladimir Putin.
In response, Mr Obama said he signed a new executive order on Thursday giving the US authority to impose sanctions not just on individuals but also on "key sectors of the Russian economy".
More top Russian officials and other individuals will be subject to sanctions, along with a bank that provides "material support" to the Russian leadership, he said.
In Brussels, the two-day EU summit began even as Ukraine's ambassador to the United Nations Yurii Klymenko told reporters in Geneva that Mr Putin would not stop at Crimea.
"There are indications that Russia is braced to unleash a full- blown intervention on Ukraine's east and south," he said.
The EU summit started with its International Trade Committee voting to approve a package of nearly 500 million euros (S$880 million) in annual trade benefits for Ukraine.
The move will allow duty-free Ukrainian exports to begin flowing into the EU late next month, well before a proposed bilateral free-trade accord with the 28-member bloc comes into effect later this year to seal the deal on Kiev's historic shift away from Russia.
The move is an important step to revive the trade and aid accord with Ukraine that was rejected by ousted president Viktor Yanukovich in November in favour of cash from Moscow.
But the EU appeared to be divided on levying actual sanctions against Russia, reported The Guardian after examining a draft of a summit statement.
A senior German government official made plain that there was "little stomach in Berlin to move to the kind of trade or economic sanctions that could hurt Russia", as an escalating sanctions war could damage Germany and much of the EU.
Indeed, German Chancellor Angela Merkel said in a speech to Parliament that financial sanctions will be discussed but no agreement on it is expected.
So far, the EU has frozen the assets of and placed a travel ban on 21 Russians and Crimeans, following similar moves by the US, and is expected to add a dozen more names to that list.
The summit is also likely to cancel a planned meeting of EU and Russian leaders in Sochi in June, The Guardian reported.
Such moves, mocked by Mr Putin and others in the Kremlin, fall far short of the tough financial and trade sanctions needed to hit Moscow where it hurts, diplomats and analysts say.
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