The UN refugee agency has raised the alarm over the rapid build up of migrants on the Greek Macedonian border. The bottleneck began after Macedonia imposed tight controls over a week ago, and threatened to shut the crossing altogether. br br RT LIVE br Subscribe to RT! br Like us on Facebook Follow us on Twitter Follow us on Instagram Follow us on Google+ Listen to us on Soundcloud: br RT (Russia Today) is a global news network broadcasting from Moscow and Washington studios. RT is the first news channel to break the 1 billion YouTube views benchmark.