An Associated Press reporter says warning shots were fired on Saturday as pro-Russian forces refused to let a foreign military mission enter Crimea.
The multinational group of military officers from the Organisation for Security and Cooperation in Europe attempted to enter the embattled peninsula from the north, but was stopped by armed men.
Warning bursts of automatic weapons fire were fired into the air, and the officers were told they had no authorization to enter Crimea, according to an AP reporter accompanying them.
No injuries were reported.
Poland evacuates consulate in Crimea
Polish Foreign Minister Radoslaw Sikorski said on Saturday Poland had evacuated its consulate in Ukraine's Crimea due to disturbances by Russian forces.
Sikorski said on Twitter: "Because of continuing disturbances by Russian forces there, we have reluctantly evacuated our consulate in Crimea, Ukraine."
The consulate is in Sevastopol, the home of both Russia's Black Sea Fleet and the Ukrainian navy, where Russian troops drove a truck into a missile defence post and took control of it overnight.