European Union foreign ministers added 13 people to their visa ban and asset freeze list over Ukraine’s crisis.

Ukraine’s police and security forces are “helpless” to quell unrest in two eastern regions bordering Russia, the country’s president has said.

Pro-Russian insurgents dug in across eastern Ukraine, fortifying their positions around seized buildings and erecting fresh barricades even as Ukrainian tanks took up positions outside one eastern city now controlled by armed men.

Ukraine’s acting president Oleksandr Turchynov has called for the deployment of United Nations peacekeeping troops in the east of the country, where pro-Russian insurgents have occupied buildings in nearly 10 cities.

Pro-Russian separatists have seized a police building in yet another city in Russian-leaning eastern Ukraine, defying government warnings that it was preparing to act against the insurgents.