(AGI) Brussels, June 27 - EU leaders have given Russia untilMonday to change policy on Ukraine or face the prospect oftougher sanctions. In a statement on Friday, the 28 EuropeanUnion leaders said Moscow had to take four steps to de-escalatethe situation in eastern Ukraine, including providing clearbacking of the Ukrainian government's peace plan, by MondayJune 30. Other conditions include Russia's agreement to aceasefire verification mechanism monitored by the EU, allowingthe Ukrainian authorities to resume control of the bordercheckpoints at Izvarino, Dolzhanskiy and Krasnopartizansk, andthe release of all hostages, including OSCE observers. . .