Military spokesman Vladislav Seleznyov said the separatist forces, backed by tanks, attacked the town of Vuhlehirsk on Thursday and government troops were fighting to push them out. September’s cease-fire deal signed in the Bealarusian capital, Minsk, envisaged a pullback of heavy weapons and other steps to end hostilities in eastern Ukraine, where a separatist insurgency erupted in April following Moscow’s annexation of Crimea. [...] the Belarusian Foreign Ministry said representatives of Ukraine, Russia, pro-Russian rebels and the Organization for Security and Cooperation in Europe are to hold peace talks Friday in Minsk. In another development, a Moscow court arrested a mother of seven on treason charges for providing Ukraine with information on Russian troop movements.