Russia has warned Ukraine not to use military force against pro-Moscow protesters in eastern Ukraine.
A presidential decree issued by acting President Oleksander Turchynov calling on Russian militants to disarm and leave occupied government buildings or face full scale “anti-terrorist” action has now passed.
World leaders fear a dangerous escalation as clashes spread in eastern Ukraine.
Authorities in Kyiv are determined not to allow a repetition of what happened in Crimea, annexed by Russia last month.
Moscow has warned they will protect the regions pro-Russian communities.
The US has called on Moscow to explain the build-up of a well armed force of some 40,000 personal along the Ukraine border.