The White House confirmed that the CIA chief John Brennan visited Kiev last weekend, where he held a series of secret meetings with the current leaders of Ukraine, Reuters reports.

White House spokesman Jay Carney told reporters that the CIA director was in Kiev as part of a trip to Europe.

"Senior level visits of intelligence officials are a standard means of fostering mutually beneficial security cooperation including US-Russian intelligence collaboration going back to the beginnings of the post-Cold War era," Carney said.

"US and Russian intelligence officials have met over the years. To imply that US officials meeting with their counterparts is anything other than in the same spirit is absurd," he said.

Russian Foreign Minister Sergei Lavrov on Monday said Moscow would like Washington to explain reports in the Russian media that CIA director John Brennan visited the Ukrainian capital at the weekend.

"We would like to understand the meaning of reports about an urgent visit of CIA director Mr Brennan to Kiev," Lavrov told reporters in Moscow. "So far we have not been given any explanations that would be reasonable."