Ukraine's acting President Oleksander Turchinov has expressed concerns about "signs of separatism" in the mainly Russian-speaking Crimea.
Protesters in the south of the country have staged demonstrations against Ukraine's new leaders since President Viktor Yanukovich was ousted.
A Russian-speaking mayor has also been appointed in Sevastopol, where Russia's Black Sea fleet is based.
Turchinov said in a press statement anyone who is held responsible for separatist moves should be punished.
Ukraine's interim President has expressed concerns about signs of separatism as opposition in Russian-speaking regions grows.
Hundreds of Ukrainians and journalists flocked to the presidential palace, as reports emerged that President Yanukovich had left the city.
Vitali Klitschko was met with boos from anti-government protesters, as he attempted to convince them a peace deal is best course of action.