The Pentagon is sending some 700 paratroopers to Iraq to guard US-operated prisons as it prepares to open a fourth major prison and leave Abu Ghraib, the site of its worst prisoner torture scandal to date. The prison population in Iraq has doubled in the past six months amid a series of US-led offensives. Next month, the US military is expected to complete a new detention center called Fort Suse to hold 2000 prisoners in northern Iraq. The Pentagon says there are currently about 12,000 prisoners in US military detention facilities in Iraq.