Nato has warned Russia that further intervention in Ukraine would be a “historic mistake” with grave consequences. Secretary-General Anders Fogh Rasmussen said Moscow must pull back troops it has massed on the Ukrainian border. Ukraine has regained control of one of the government buildings occupied by pro-Russian activists in the east of the country, in the city of Kharkiv. However, armed militants are refusing to withdraw in another city, Luhansk. Moscow has said that using force to end the protests could lead to civil war. Kiev says the unrest in the east is being fomented by Russia following its annexation of the Crimean peninsula. Russia took control in Crimea – where Russian-speakers are in a majority – after a disputed referendum, which sparked Western sanctions. In other developments, More