Thousands flee Falluja amid 'humanitarian disaster' warning

A humanitarian disaster is unfolding around the embattled Iraqi city of Falluja as the Iraqi army fights to drive the so-called Islamic State out of the city.

UN figures show 80,000 residents have fled in the past few weeks, and a further 25,000 are likely to be on the move.

Aid agencies are struggling to provide food, water and shelter for them. The BBC's Alan Johnston reports.