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.
More top news
Ofcom has been asked by cable giant Virgin Media to open a formal investigation into the way the Premier League sells its TV rights
The whole tooth: Five fascinating dental facts
Newcastle boss Alan Pardew's job is under no immediate threat despite a winless start to the Premier League season.