Rebels pressed ahead with a referendum on self-rule in east Ukraine on Sunday and fighting flared anew in a conflict that has raised fears of civil war and pitched Russia and the West into their worst crisis since the Cold War. Clashes broke out around a television tower on the outskirts of the rebel stronghold of Slaviansk shortly before voters made their way to polling stations through streets blocked by barricades of felled trees, tyres and rusty machinery. "I wanted to come as early as I could," said Zhenya Denyesh, a 20-year-old student voting at a three-storey concrete university building. In nearby Mariupol, scene of fierce fighting last week, officials said there were only eight polling centres for half a million people.