"U.S. considers action with Iran against Iraq insurgent onslaught"

(Reuters) - The United States is contemplating talks with its arch-enemy Iran to support the Iraqi government in its battle with Sunni Islamist insurgents who routed Baghdad's army and seized the north of the country in the past week.

The stunning onslaught by militants from the Islamic State of Iraq and the Levant threatens to dismember Iraq and unleash all-out sectarian warfare across a crescent of the Middle East, with no regard for national borders that the fighters reject.

Joint action between the United States and Iran to help prop up the government of their mutual ally Nuri al-Maliki, Iraq's Shi'ite prime minister, would be a major turn of events after hostility dating to Iran's 1979 revolution, and demonstrates the urgency of the alarm raised by the lightning insurgent advance.

ISIL seeks a caliphate ruled on medieval Sunni Muslim precepts in Iraq and Syria, and is also fighting Syria's Iran-backed government. It considers all Shi'ites to be heretics deserving death and has boasted of massacring hundreds of Iraqi troops who surrendered to its forces last week.