US says airstrikes have cut deeply into Islamic State defense of Iraqi city of Ramadi

Iraqi security forces look at confiscated Islamic State group weapons and ammunition after regaining control over the last week, in Ramadi, Iraq's Anbar province, 70 miles (115 kilometers) west of Baghdad, Thursday, Dec. 10, 2015. Following significant advances on Ramadi Tuesday, Iraqi forces are now preparing to push into the city center from the southwest and the north. Tuesday’s advances, the most significant incursion into Ramadi since the city fell to the Islamic State group in May, have placed Iraqi forces along the southwest edge of Ramadi in the Tamim neighborhood and just north of the city at the former Anbar operations command. An Islamic State flag is seen hung upside down. (AP Photo/Osama Sami) (The Associated Press)

Iraqi security forces take combat positions on the front line with Islamic State group militants in Ramadi, capital of Iraq's Anbar province, 70 miles (115 kilometers) west of Baghdad, Thursday, Dec. 10, 2015. Following significant advances on the Anbar provincial capital Ramadi Tuesday, Iraqi forces are now preparing to push into the city center from the southwest and the north. Tuesday’s advances, the most significant incursion into Ramadi since the city fell to the Islamic State group in May, have placed Iraqi forces along the southwest edge of Ramadi in the Tamim neighborhood and just north of the city at the former Anbar operations command. (AP Photo/Osama Sami) (The Associated Press)

Defense Secretary Ash Carter answers a reporter's question during his joint news conference with Indian Defense Minister Manohar Parrikar, Thursday, Dec. 10, 2015, at the Pentagon. (AP Photo/Cliff Owen) (The Associated Press)

The U.S. military says airstrikes over the past week have killed about 350 Islamic State fighters in the Iraqi city of Ramadi — and that may have reduced by half the number of fighters defending the city.

IS took Ramadi seven months ago.

Col. Steve Warren, a spokesman for the U.S. military in Baghdad, tells reporters at the Pentagon that despite these losses, IS defenders still hold much of central Ramadi.

Warren says Iraqi government forces are advancing slowly because they face booby traps and mines.

Separately, Defense Secretary Ash Carter says Iraqi progress in retaking Ramadi has been "disappointingly slow." He's declining to predict how long the fight will last, but says he has no doubt Ramadi will fall.