AP: Iraqi, Kurdish and U.S. officials have spoken of possible links between Iran and Iraqi insurgent groups. Here's a look
at the various parties: ... By Associated Press

Iraqi, Kurdish and U.S. officials have spoken of possible links between Iran and Iraqi insurgent groups. Here's a look at the various parties:

TAWHID AND JIHAD: Headed by Jordanian Abu Musab al-Zarqawi, who has proclaimed his allegiance to al-Qaida. Claimed responsibility for several beheadings and car bombings in Iraq. Believed to be based in the central Iraqi city of Fallujah.

ANSAR AL-ISLAM: Formed in the Kurdish parts of Iraq. Later believed to have incorporated Arab al-Qaida members fleeing U.S. strikes on Afghanistan. Group had bases along Iranian-Iraqi border that were bombed and attacked by Iraqi Kurdish and U.S. Special Forces at the start of the Iraq war. Al-Zarqawi is believed to have played a key role in the group after he fled Afghanistan.

IRANIAN GOVERNMENT: Led by theocratic clerics but with a reformist government that is struggling to assert itself.

REVOLUTIONARY GUARD: Shock troops of Iran's Islamic Revolution. A well-funded force of 200,000 that is independent of the armed forces and answers directly to the Islamic leadership and not elected officials.

MAHDI ARMY: Radical cleric Muqtada al-Sadr's militia, only insurgent group based among Iraq's Shiite Muslim majority.

PATRIOTIC UNION OF KURDISTAN, KURDISTAN DEMOCRATIC PARTY: The leading Kurdish groups in northern Iraq. Groups are both secular and have supported the United States in Iraq.