Ukrainian self-defense fighters who clashed with armed pro-Russian separatists on Friday are at the forefront of Kiev's efforts to prevent the country from splitting.
Co-funded by Ihor Kolomoisky, one of Ukraine's richest men, they play a more assertive role than the unarmed miners and metalworkers working for another oligarch, Rinat Akhmetov, who more recently spoke against the rebels.
At least two people were killed in Friday's firefight involving the pro-Ukrainian "Donbass Battalion" allied to Kolomoisky. The violence took place two days before a presidential election that the separatists have vowed to disrupt.