Nato has announced a review into its cooperation with Russia due to the ongoing crisis in Ukraine, after they suspended all meetings with Russia.
Secretary-General Anders Fogh Rasmussen said officials would no longer hold staff-level meetings with their Russian counterparts, as they planned to step up engagement with Ukraine's civilian and military leadership.
"We have also decided that no staff-level civilian or military meetings with Russia will take place for now," Rasmussen told reporters after a meeting between NATO and Russian officials in Brussels.
The alliance will also suspend planning for a joint mission linked to Syrian chemical weapons, Mr Rasmussen added.
Barack Obama warned Russia that the West will be forced to apply a cost to Moscow if it fails to change course in its dispute with Ukraine.
The ballot paper that the people of Crimea will use in Sunday's referendum was published today
Vitali Klitschko's visit to the eastern city of Donetsk is clearly an attempt to try to ease the divisions with Ukraine.