The New York Sun‘s Eli Lake reports:

WASHINGTON – Iran is supporting both Sunni and Shiite terrorists in the Iraqi civil war, according to secret Iranian documents captured by Americans in Iraq.

The news that American forces had captured Iranians in Iraq was widely reported last month, but less well known is that the Iranians were carrying documents that offered Americans insight into Iranian activities in Iraq.

An American intelligence official said the new material, which has been authenticated within the intelligence community, confirms “that Iran is working closely with both the Shiite militias and Sunni Jihadist groups.” The source was careful to stress that the Iranian plans do not extend to cooperation with Baathist groups fighting the government in Baghdad, and said the documents rather show how the Quds Force – the arm of Iran’s revolutionary guard that supports Shiite Hezbollah, Sunni Hamas, and Shiite death squads – is working with individuals affiliated with Al Qaeda in Iraq and Ansar al-Sunna.

There were reports in the Iraqi press of Iran backing Al Qaeda in Iraq last spring.