An offensive by insurgents that threatens to dismember Iraq seemed to slow on Saturday after days of lightning advances as government forces regained some territory in counterattacks, easing pressure on the Shiite-led government in Baghdad.

As Iraqi officials spoke of wresting back the initiative against Sunni militants, neighboring Shiite Iran held out the prospect of working with its longtime U.S. archenemy to help restore security in Iraq.

U.S. President Barack Obama said on Friday he was reviewing military options, short of sending troops, to combat the insurgency.