Kerry condemns Russian aggression against Ukraine

US Secretary of State John Kerry Sunday denounced Russia's "incredible act of aggression" against Ukraine, suggesting a set of sanctions in response.

The top American envoy called on Russia to consider other options to address its concerns about the treatment of ethnic Russian and minority populations in Ukraine, echoing a message broached by US President Barack Obama in his 90-minute talks with Russian President Vladimir Putin over the phone a day ago.

"It's an incredible act of aggression," Xinhua quoted Kerry as saying on CBS's " Face the Nation" programme. "It is really a stunning, willful choice by President Putin to invade another country."

Putin Saturday asked for and was granted authorisation to use military force to protect Russian interests in Ukraine, a move that has sparked an immediate outcry from western countries.

Ukraine's interim President Oleksandr Turchynov Friday appealed to Putin to stop Russia's "naked aggression".

He urged Putin to withdraw from the Crimea peninsula in southern Ukraine, where Russia has its Black Sea Fleet based, as airports and parliament and government buildings there have been occupied by armed personnel.