Pro-Moscow protesters in eastern Ukraine took up arms in one city and declared a separatist republic in another yesterday and the new build-up of tensions continues this morning.

The Kiev government has launched what it calls “anti-terrorist” operations in the eastern city of Kharkiv and arrested about 70 separatists. Moscow has responded by demanding Kiev stop massing military forces in the south-east of the country.

Russia’s own forces remain massed just over the border and Ukrainian President Oleksander Turchinov said Moscow was attempting to repeat “the Crimea scenario”.

Washington has warned Vladimir Putin against moving “overtly or covertly” into eastern Ukraine and said there was strong evidence that pro-Russian demonstrators in the region were being paid.

There is also a standoff over gas. Kiev appears to have made no payments to Gazprom, missing a deadline last night to reduce its $2.2 billion debt. Gazprom has not said what action it may take. In previous years, gas disputes between Moscow and Kiev have hurt supplies to Europe.