The first confusing reports are coming in of a US military helicopter having been either shot down or crashed on the centre of Baghdad.
The area is sealed off and heavy fighting is taking place at the scene.
A spokesman for the US military in Iraq said the reports were being checked, but could give no further information.
Other reports claim a rocket pod on a helicopter caught fire and was jettisoned. The US has lost more than 50 military helicopters in Iraq.
On the 4th anniversary of the "liberation" of Baghdad as traffic was banned from Central Baghdad and a curfew was imposed, 10 US soldiers died in Iraq bringing the April total so far to 35. 3 US soldiers died yesterday when a bomb was detonated nearby their patrol in Baghdad. Another was killed in an attack south of the capital; and 2 who died of combat wounds sustained north of the capital, in Diyala and Salahuddin provinces. On Saturday, 4 U.S. soldiers were killed in an explosion near their vehicle in Diyala.
Centre Michael Doleac (puc) of the Miami Heat heard that his bro, Blackhawk pilotArmy 2nd Lt. Kenneth Doleac, 25, was piloting a Black Hawk helicopter just south of Baghdad last Thursday and was shot down by small arms fire.''From what I've heard from him, it was he and another helicopter flying,'' Doleac said.
"They got hit, it was just small arms fire, and they ended up going down. He was able to put it down. A couple of his guys got hit, but no one was injured seriously. He was able to put the helicopter down. The other Black Hawk that was with him wound up coming back in a couple of minutes and picked them up."Elsewhere supporters of Moqtada al Sadra marched from Kufa to neighboring Najaf, 100 miles south of Baghdad, with two cordons of Iraqi police lining the route.
Al Sadra did not appear but Nassar al-Rubaie, head of al-Sadr's bloc in parliament addressed the crowd demanding
"The enemy that is occupying our country is now targeting the dignity of the Iraqi people,After four years of occupation, we have hundreds of thousands of people dead and wounded."
Salah al-Obayd a Sadrist leader in Najaf called the rally a "call for liberation."
"We're hoping that by next year's anniversary, we will be an independent and liberated Iraq with full sovereignty."
Iraqi soldiers in uniform joined the crowd, which was led by at least a dozen turbaned clerics -- and a rare sight of episcopal solidarity, one Sunni.
All this failed to prevent the daily slaughter as a truck bomb exploded near the Mahmoudiya General Hospital yesterday, at least 18 were foiund dead and 23 were severely wounded. The pickup truck loaded with artillery shells blew apart several buildings in a warren of auto repair shops.
Violence in Iraq remained as relentless with at least 47 people killed or found dead in violence yesterday, including 17 execution victims dumped in the capital.
..and so it goes on