Police re-captured the administrative headquarters of the eastern Ukrainian city of Donetsk and have around 68 pro-Russian protesters in custody who are being questioned over the occupation.

The US Secretary of State has said that there were "very serious repercussions that can flow" from the invasion of Ukraine territory and outlined a raft of economic sanctions that could leave Russia isolated.

John Kerry said that the appointment of Ukraine's interim government was "a democratic process" adding that "President Putin ought to respect that".

US Secretary of State John Kerry. Credit: Arno Burgi/DPA/Press Association Images

He said Russia needed to "think very carefully" about what it's doing, adding that there are "serious implications" and a "price attached to this sort of behaviour".