Pro-Russian activists detained Wednesday Ukraine's Navy Chief Serhiy Hayduk, short after taking control of the navy's HQ.

Russian website Lenta.ru, citing Kriminform news agency, explains that Hayduk had ordered "the use of weapons against civilians".

Ukraine's army has not confirmed that he issued such an instruction.

Earlier on Wednesday, one man was reportedly killed in an attack on a Ukrainian base in Crimea's capital Simferopol, and Ukraine's navy headquarters in Sevastopol were stormed and seized by 300 armed men, backed by local inhabitants.

Minutes later, a Russian flag was waving over the building.

According to the BBC, Ukraine's Defense Mnister Ihor Tenuykh and First Deputy Prime Minsiter Vitaly Yarema travelled to Crimea in an attempt to ease tensions, but were not allowed to enter the peninsula.

After Crimean population voted in favour of joining Russia on March 16 and Vladimir Putin signed a decree incorporating the region into the Russian Federation, Crimea virtually perceives the administrative borderline between the autonomous region and the mainland as a border between Crimea and Ukrane, which still claims sovereignty to the peninsula.