Kyiv's energy generating company Kyivenergo has reported a hacker attack, the company's press service has told the Kyiv-based Interfax-Ukraine news agency.

"We were attacked. Two hours ago, we had to turn off all our computers. We are waiting for permission from Ukraine's Security Service (SBU) to switch them back on," Kyivenergo's press service said.

Ukraine's National Energy Company Ukrenergo, meanwhile, told Interfax-Ukraine that the company's computer systems were also affected, but not seriously.

"We experienced problems with computers. But everything is stable and under control. Conclusions about the incident will be drawn after a check of the systems," the company said.

A number of state banks and companies also complained about hacker attacks, according to Interfax-Ukraine.

Kyivenergo is the monopoly energy supplier to almost all energy consumers in the capital, with the exception of the Darnytsky heat and electric plant.