Crimea declared a state of emergency on Sunday after its main electricity power lines from Ukraine were blown up, leaving the peninsula in darkness after the second such attack in a matter of days.

Crimea depends on Ukraine for its electricity supplies, providing only 30 percent of its own energy, according to the regional government.

Russia's emergency situations ministry said Sunday morning they had managed to partially reconnect the cities of Simferopol, Feodosia, Yevpatoria and Yalta using generators after two pylons were brought down.

So far, Crimea - home to 1.9 million people - has enough fuel to keep the gas and diesel-powered generators running, authorities said.

In the port city of Sevastopol, electricity began shutting off around midnight and cut off completely at 2 am, although different districts have since had brief periods of power in what appears to be organized rolling blackouts by authorities.

Cable and mobile Internet stopped working, although there was still cell phone coverage, and water supplies to high-rise buildings halted.

The attack has raised concerns the Black Sea peninsula, will not have enough energy after the other two main power lines supplying the region were blown up on Friday.

"On November 22, there was a switch-off of electricity coming into Crimea from Ukraine," the Crimean branch of Russia's emergency situations ministry said in a statement.

"By decision of the head of the Crimean republic, a state of emergency has been introduced on the peninsula," the ministry said.

"All socially significant or potentially dangerous installations ... are being fuelled with reserve sources of energy."

It added that power to housing would be supplied "on a rolling schedule" set by the regional power company.

Mikhail Sheremet, the first deputy premier of Crimea, said the peninsula could only supply half its power needs at most using diesel generators and renewable sources such as wind and solar power, Russia's TASS news agency reported.

The four power lines that supply Crimea with electricity from Ukraine were first attacked in the early hours of Friday in Ukraine's Kherson region bordering Crimea, in blasts that downed two lines and damaged the other two.