In a rare joint statement today, the 28 leaders voiced concern over what they said was Russian support for pro-Moscow rebels who have made large gains in eastern Ukraine and targeted the key port city of Mariupol.
"We condemn the killing of civilians during the indiscriminate shelling of the Ukrainian city of Mariupol on 24 January 2015. We note evidence of continued and growing support given to the separatists by Russia, which underlines Russia's responsibility," they said.
EU leaders would review the situation at their next summit in Brussels on February 12, the statement added.
Under Brussels rules the foreign ministers will task the European Commission, the bloc's executive arm, with drawing up new sanctions, which would then have to be approved by the leaders.
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The largely ignored Minsk peace plan dating from September has failed to stop a conflict which has now claimed around 5,100 lives since March, with fighting now as bad as ever following a quieter period over the Christmas-New Year holiday.
It first slapped asset freezes and travel bans on Crimean, Ukrainian rebel and Russian figures, including some close to Putin. The shooting down of Malaysia Airlines flight MH17 over eastern Ukraine in July then stung Brussels into adopting much tougher economic sanctions, hitting the country's defence, energy and finance sectors.
After the Mariupol attack on Saturday, EU foreign affairs chief Federica Mogherini announced the extraordinary meeting of European foreign ministers to map out the bloc's response to the latest violence.