The leaders of the 28 European Union nations issued a rare joint statement on Tuesday telling ministers "to consider any appropriate action" after a bloody upsurge in fighting around the key port city of Mariupol by pro-Russia rebels.
Economic sanctions will not be approved at Thursday's meeting but the foreign ministers are expected to ask the European Commission to draw up possible further steps so that leaders can make a decision at a summit on February 12, the sources said.
A second European source confirmed that the ministers were headed towards recommending more individual sanctions, adding that it was "not yet sure if just separatists or if Russians too" would be targeted.
"Sectoral sanctions will not be brought up," the source added.
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Since Russia's annexation of Crimea in March 2014 the EU has slapped asset freezes and travel bans on dozens of individuals ranging from associates of Russian President Vladimir Putin to Ukrainian separatist leaders.
But divisions between EU nations over the extent of sanctions against their huge eastern neighbour are likely to resurface at Thursday's meeting in Brussels.
"The question of economic sanctions is open. With the declaration (on Thursday) everyone will probably have his proper interpretation on what it exactly means," the EU source said.
"What we need is a formula which demonstrates the unity of the EU in this question."