500,000 Iraqis flee Mosul as militant takeover continues [VIDEO]

Insurgents advanced on Iraq’s biggest oil refinery on Wednesday, a day after overrunning the city of Mosul in a spectacular show of force which triggered an exodus of half a million refugees.

Sunni militants from an al Qaeda splinter group overran Mosul – Iraq’s second-largest city – on Tuesday following a weekend of heavy fighting.

Photo: People flee from Mosul, Iraq. (Getty Images via NBCNews.com)