In a fresh warning, U.S. Secetarry of State John Kerry cautioned Russia there will be more sanctions if it tries to sabotage presidential elections in Ukraine and does not halt its support for separatists in the country.

"We are not going to sit idly by while Russian elements fan the flame of instability," said Kerry speaking at the State Department in Washington after meeting with the European Union's foreign policy chief, Catherine Ashton.

"Ukraine has shown remarkable restraint. They have been committed to move their country forward through non-violence," said Kerry expressing concern over efforts by pro-Russian separatists to "contrive a bogus independence referendum."

GRAFELBERGNOTICIAS