SIMFEROPOL, Ukraine (AFP) - Crimea's separatist authorities moved against energy companies on Monday in their first nationalisations after deciding all Ukrainian state property would be transferred into Crimean ownership.

Shortly after voting to declare independence from Ukraine, the regional assembly moved to nationalise the local assets of state-owned oil company Chornomornaftogaz in a decision that also included the "continental shelf and exclusive economic zone" in the Black Sea.

The assets of two more energy companies, Ukrtransgaz and the Feodosiya oil and gas company, were also nationalised.

Chornomornaftogaz is the main energy company in Crimea, with oil and gas exploration and extraction operations in the Black Sea and Sea of Azov. In 2012, it extracted some 1.2 billion cubic metres of gas.

A day after Crimea voted overwhelmingly to split from Ukraine and become part of Russia, the regional assembly in Simferopol announced that: "All establishments, businesses and other organisations of Ukraine or with Ukrainian participation on the territory of Crimea will belong to Crimea."