Heavy fighting between Ukrainian troops and Russia-backed separatists erupted in eastern Ukraine on Tuesday, casting doubt on the Ukrainian president’s plans for a peace settlement. At least one Ukrainian soldier was killed and five injured on Tuesday morning in a separatist attack on government positions in four areas across the front line, the government’s headquarters for the operation in the east said. Separatists in the Luhansk region said they were forced to respond to what one rebel official described as a “deadly provocation.” Luhansk People’s Police representative Yakov Osadchiy, in comments carried by Russian news agencies alleged that authorities in Kyiv mounted the attack in order to derail plans of a heavy weaponry pullback in the area....