Ukrainian authorities have detained four suspects after an explosion killed at least two people and wounded fifteen others at a peace march in the government-controlled city of Kharkiv.<br /><br /> An aide to the head of the security services said the suspects were Ukrainian citizens who had received weapons and training from Russia.<br /><br /> Kharkiv is the largest city in Ukraine’s mainly Russian-speaking east, and lies more than 220km away from the conflict zone where fighting continues despite a ceasefire deal.<br /><br /> The rally was part of a series of events across Ukraine over the weekend to commemorate the deaths of 100 protesters during the popular uprising which ousted pro-Russian President Viktor Yanukovych last year and led to the conflict in the east which has claimed more than 5,000 lives.
