SIMFEROPOL, Ukraine (REUTERS) - A Ukraine state gas company Chornomornaftogaz official said its rigs off Crimea were not occupied by armed men, after a regional separatist leader said on Thursday that local authorities were guarding the facilities.

Mr Vladimir Konstantinov, speaker of the Crimean regional assembly which is seeking to leave Ukraine and unite with Russia, had told Russian news agency RIA: "These fields and platforms will become the property of the Crimean Republic in their entirety. We are already guarding them.

"They are our fields and we will fight for them."

Another Crimean official said on Wednesday that the region was taking ownership of Ukrainian state companies on its territory, including the offshore fields of Chornomornaftogaz, a subsidiary of the main state energy company Naftogaz.

An official at Chornomornaftogaz in the Crimean capital Simferopol told Reuters by telephone that there had been no sign on or around its production and exploration facilities of the Russian-backed armed groups which seized control of the Black Sea peninsula last week.

"Our rigs are in international waters and there are no armed people on or around them," he said. "We have no guards at all and only our own staff are on the rigs."

Ukraine, which consumes around 50 billion cubic metres of gas per year, produces about 20 bcm of its own both on and offshore and covers the rest of the needs with imports, mostly from Russia.

Officials in the new Ukrainian authorities in Kiev, in power since protesters overthrew a pro-Moscow president last month, have denounced as illegitimate a referendum being held on Sunday that the new leadership in Simferopol expects to give them a mandate to transfer the territory to Russian control.

Mr Konstantinov told RIA that Russian companies such as Gazprom should be involved in Crimea's oil and gas production.