LISBON, Portugal — Clearly exasperated by its latest moves to break up Ukraine, European Union leaders toughened their position on Russia during a day-long summit Thursday by agreeing to impose political sanctions against Moscow.
"We know from our history that turning a blind eye when nations are trampled over and their independence trashed stores up far greater problems in the long run," said British Prime Minister David Cameron.
"We must stand up to aggression, uphold international law and support people who want a free, European future," he told reporters after the meeting in Brussels.
All 28 EU leaders agreed to suspend talks on a cooperation agreement with Russia and negotiations on visa liberalization — an issue that’s been a key priority for Russia as it seeks to make travel to the West easier for its citizens.
The EU agreed that tougher sanctions could be phased in if Russia fails to open negotiations with the Ukrainian government or further escalates a crisis that NATO Secretary General Anders Fogh Rasmussen characterized as "the gravest threat to European security since the end of the Cold War."
In a statement, the EU said that further moves could include travel bans and asset freezes for Russian officials like those announced by the United States on Thursday, and eventually "severe and far-reaching consequences" affecting "a broad range of economic areas."
Although Cameron acknowledged that such sanctions could hurt European countries — not least Britain, which has benefited from Russian investment in London — he said EU states were prepared to pay the price.
The summit also agreed to speed up moves to support Ukraine, including a $15 billion aid package, opening EU markets to Ukrainian goods and bringing forward the signing of a political cooperation deal.
The EU leaders had been divided going into the summit. Several nations were wary sanctions would harm mediation hopes or undermine their economic ties with Russia.
However, the decision by pro-Moscow lawmakers in Crimea to hold a referendum on attaching the restive region to Russia galvanized opinion, bringing more hesitant leaders on board.
Britain, France and Germany in particular formed a united front in demanding Russian President Vladimir Putin back down.
"We want to continue our relations with Russia which are of mutual interest, but what has happened in Ukraine, in particular events on the Crimea peninsular, demand a response," said German Chancellor Angela Merkel. "We are ready and willing to act."
Separately, the EU formally slapped a travel ban and asset freeze on 18 former Ukrainian officials — headed by ex-President Viktor Yanukovych — who are accused of embezzlement or involvement in violence that left more than 80 people dead in Kyiv last month.
Merkel said the EU would work closely with the United States to coordinate any moves against Russia.
The Union is applying a twin-pronged approach, seeking to coax or cajole Putin to back down in Crimea and negotiate a settlement with the new Ukrainian government, while actively working to bolster the authorities in Kyiv.
The cooperation measures the EU will now fast track include essential parts of the wide-ranging agreement designed to tie Ukraine to the Western bloc. Yanukovych’s decision to abandon such a deal with the EU under Russian pressure last year precipitated the demonstrations that prompted the current standoff.
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Back then, European leaders failed to convince Putin that opening Ukraine to the West wouldn’t harm Russian interests. Now the EU is moving ahead in defiance of Putin's threats to split or destabilize the country. However, leaders said they would continue to seek a negotiated settlement.
"The whole effort of Europe will be concentrated on seeking to reduce tensions," said French President Francois Hollande. A priority will be to set up a "contact group" of negotiators including Russia to open talks on a solution.
Not all EU members were entirely happy with the summit outcome. The leaders of Poland and Lithuania said they would have preferred the EU to move further down the sanctions road.
"I'm satisfied how the United States is moving. I'm a little bit satisfied that the European Union is trying to catch up," said Lithuanian President Dalia Grybauskaite. "That the European Union has some sanctions is a step forward."