UN fears major Syrian government assault on town of Yabroud

GENEVA (Reuters) - The United Nations voiced concern on Friday at a military build-up near the rebel-held Syrian town of Yabroud, saying it feared a "major assault" by government forces and stressed that Damascus had a legal duty to allow civilians to leave. "We have received reports from within Syria that there have been numerous aerial attacks and shelling along with a military build-up around the town, suggesting a major assault by land may be imminent" on the town of 40,000-50,000 people, U.N. human rights spokesman Rupert Colville told a news briefing. Some 500-600 families have already fled and arrived in Arsal, Lebanon, citing "their fear of this attack" and the U.N. refugee agency is "bracing for a big influx" across the Lebanese border, UNHCR spokeswoman Melissa Fleming told reporters. (Reporting by Stephanie Nebehay; Editing by Robin Pomeroy)