Ukrainian forces are said to have launched an operation to retake the town of Slovyansk, which has been in the hands of pro-Russian separatists.<br /><br /> Both sides say there have been casualties.<br /><br /> Ukraine’s Interior Minister Arsen Avakov says one helicopter pilot was killed and others wounded after pro-Russian forces fired anti-aircraft missiles.<br /><br /> “Against Ukraine’s special forces, terrorists used heavy artillery, including grenade launchers and portable anti-aircraft missile launchers. One pilot is dead and there are wounded,” Avakov posted on his Facebook page.<br /><br /> On the rebel side, the self-declared mayor of the town, Vyacheslav Ponomaryov, was quoted by Russia’s Interfax news agency as saying two Ukrainian military helicopters had been shot down, one pilot killed and another detained.<br /><br /> Earlier gunfire was heard, and a Reuters photographer saw a helicopter opening fire on the outskirts of the town, where pro-Russian forces have built barricades and set up checkpoints.<br /><br /> The scale of the operation is not clear but it does appear to be the first significant military response from Kyiv since pro-Russian rebels took control of government buildings in several towns across eastern Ukraine.
