Ukrainian accusations that Moscow was behind cyber attacks on President Petro Poroshenko's official website are baseless, Kremlin spokesman Dmitry Peskov said on Wednesday.

"The lack of any details confirms the groundlessness of the accusations," Peskov told reporters during a regular conference call.

Ukraine accused Russia on Tuesday of carrying out an organised cyber attack on Poroshenko's website in response to Kiev's decision to impose sanctions against a number of major Russian internet businesses.