Activists chant slogans and carry the Iraqi national flag on Friday during a mass demonstration in Baghdad, Iraq, that called for the immediate withdrawal of U.S. military forces. Photo by Ahmed Jalil/EPA-EFE

Jan. 24 (UPI) -- Millions of Iraqi citizens gathered for a mass demonstration in the capital Baghdad on Friday to demand the withdrawal of all U.S. forces, which have now been in Iraq on some level for nearly 20 years.

The "million man" protest march was organized by a top Shiite cleric and supported by Iranian-backed militia groups.


Sayed Sadiq al-Hashemi, head of the Iraqi Center for Studies, said more than 2.5 million people turned out for Friday's rally.

Iraqi Shiite cleric Muqtada al-Sadr urged followers this week to join the protest as a show of opposition to the U.S. military presence.

Al-Sadr called Friday for all U.S. bases in Iraq to be shut down and the closure of Iraqi airspace to American warplanes and surveillance aircraft. He also warned that U.S. refusal to leave would lead Iraqi leaders to view the U.S. military as an occupying force.

Earlier this month, Iraqi Parliament passed a resolution in a bid to expel all foreign forces after a U.S. airstrike killed a top Iranian military commander and a deputy. In retaliation, Tehran launched missile attacks at two U.S.-held bases in Iraq.

U.S. forces arrived in Iraq in 2003 and stayed there in large numbers until the operational phase of the Iraq War ended in late 2011. American troops, however, have remained in the Middle Eastern nation in much smaller numbers for the past nine years.

The Pentagon sent 3,000 troops to Middle East this month after a Dec. 31 attack on the U.S. Embassy in Baghdad, which occurred three days before the U.S. airstrike killed commander Qassem Soleimani and set off a new wave of hostilities.

The embassy attack was blamed in part on the Iran-backed Kataib Hezbollah militia group, which was also present in Friday's march.

The government of Prime Minister Adel Abdul Mahdi has not yet ordered the withdrawal of U.S. forces in Iraq.