The UN General Assembly has approved a resolution affirming Ukraine's territorial integrity and calling the referendum that led to Russia's annexation of its Crimean peninsula illegal.
The vote on the Ukraine-sponsored resolution was 100 countries in favour, 11 opposed and 58 abstentions.
The "yes" vote was higher than many diplomats had predicted, and the fact that more than half the 193 UN member states supported the resolution reflected widespread international opposition to Russia's military intervention and takeover of the strategic Black Sea region.
Unlike the more powerful Security Council, resolutions in the General Assembly cannot be vetoed but are not legally binding.
Russia has blocked action in the Security Council where they have veto power as one of its five permanent members.
Even so, the 15-member council has held eight meetings on Ukraine, as Western powers strive to keep up the pressure on Moscow.
Before the vote, Ukraine's Foreign Minister Andriy Deshchytsia told the assembly that his country's territorial integrity and unity had been "ruthlessly trampled" by Russia, a permanent member of the Security Council entrusted to maintain international peace and security, and in direct violation of the UN Charter.
"By voting in favour of this resolution you vote in favour of the UN Charter while voting against or abstaining equals undermining it," Deshchytsia said in urging a "yes" vote.
Russia's UN Ambassador Vitaly Churkin urged a "no" vote, saying a historic injustice in Crimea has been corrected and its people had expressed their right to self-determination in wanting to join Russia.
He called the resolution "confrontational in nature" and said it would be "counterproductive" to challenge the results of the referendum.
Tymoshenko for president
Thursday's resolution came hours after former Ukrainian Prime Minister Yulia Tymoshenko announced she would run again for president in an election slated for May 25.
"I plan to run for election as president" and stand as "a candidate for Ukrainian unity," Tymoshenko, who was released from jail last month after President Viktor Yanukovich was forced by protesters to leave power, told reporters on Thursday.
The 53-year-old served twice as prime minister and ran for president in 2010, only to be narrowly beaten by Yanukovich in a run-off vote.
Yanukovich subsequently launched a campaign against Tymoshenko and her allies, and she was jailed in 2011 for abuse of office linked to a gas deal she brokered with Russia in 2009.
She served two years of a seven-year term, mainly under prison guard in a hospital in Kharkiv, before being released when Yanukovich fled on February 20 and was subsequently ousted by parliament.
Her announcement coincided with the International Monetary Fund's pledge to provide up to $18bn in loans to prop up Ukraine's sinking economy.
Arseniy Yatsenyuk, Ukraine's interim prime minister, has forecast more pain ahead without reforms that will affect nearly everyone in the country.
In a lengthy and passionate address to parliament, Yatsenyuk warned that Ukraine was "on the brink of the economic and financial bankruptcy" and laid out details for fixes needed to put the country back on track, including raising taxes, a freeze on minimum wage and radically higher energy prices.
The reforms will hit households hard, which is likely to severely dent the interim government's tenuous hold on power.
"We have no choice but to tell Ukraine the truth," Yatsenyuk said.
Ukraine is still battling to restore some semblance of normalcy since Yanukovich was ousted after months of protests ignited by a decision to back away from closer relations to the EU and move towards Russia.