Ukraine faces "grave consequences" from Russia for its decision to sign a trade agreement with the European Union, the deputy foreign ministry has warned.
Grigory Karasin's comments after Ukraine's president Petro Poroshenko agreed a three-year deal with the EU.
Kremlin spokesman Dmitry Peskov said Russia would take measures to protect its economy if it was negatively affected by Ukraine, Georgia and Moldova's agreements.
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Known as 'spice' and 'black mamba', the so-called legal high is suspected of contributing to deaths in male and female institutions.