The letter sent by council president Mohammed Bahr al-Ulloum, a Shiite cleric, also requested technical assistance in preparation for a general election due by the end of January 2005, council spokesman Hamid al-Kafaai told The Associated Press.
Powerful Shiite cleric Grand Ayatollah Ali al-Husseini al-Sistani had pushed for earlier elections. But last month, a United Nations team reported that elections were not possible before the June 30 handover, echoing the U.S. position.
However, because of al-Sistani's objections, the U.S. has dropped a plan to hold regional caucuses before the handover to pick that interim government.
That means that while Iraq has an interim constitution in place to guide Iraq's first elected government, there is no plan for the government that will take over this summer, before elections are held.
In other developments:
The operation launched Wednesday is called "Iron Promise" and is expected to involve thousands of U.S. troops and scores of Iraqi Civil Defense Corps soldiers.
In Wednesday's first raid, about 250 troops from the armored division's 1st Squadron, 1st Cavalry Regiment as well as 250 Iraqi soldiers fanned out across the sprawling 20th Street Market, in the city's Al-Bayaa district, which sells everything from vegetables to used car parts.
Some of the stores are suspected of supplying weapons to the rebels, said the raid's commander, Lt. Col. Chuck Williams, 40. He said the market assault was just the start of a citywide crackdown on the guerrillas.
With helicopters hovering overhead, forces in Bradley fighting vehicles and Humvees circled the market to prevent rebels from escaping the area. Troops then went store to store searching for weapons and guerrilla suspects. Few residents expressed opposition to the search and the mood was relaxed.
"There are so many places to run and hide. That's why we have to lock it down. We could easily spend a few days doing this. But we basically just want the bad guys to know that we are still here," said Maj. Gregg Softy, 38, from Hyde Park, N.Y.
In one car repair shop, U.S. troops found a pair of rocket-propelled grenade launchers and burlap sacks full of grenades. They arrested three men.
U.S. officials say they have identified 14 rebel cells across Baghdad and while raids on them in the past few months have disrupted their operations, they are still active.
The United States has urged a U.N. role in the U.S.-backed political process for Iraq, and coalition spokesman Dan Senor welcomed news of the council's invitation.
The announcement of the invitation, decided in a council meeting earlier Wednesday, followed remarks that al-Sistani and his supporters on the U.S.-appointed Governing Council were unhappy with the U.N. report issued last month that found Iraq unready for elections ahead of June 30.
Sami al-Askari said several council members did not think the return to Iraq of U.N. envoy Lakhdar Brahimi would be helpful and that Grand Ayatollah Ali al-Husseini al-Sistani would not receive him if he returned.
"It is not Brahimi's personality, but some members have some reservations about the contents of his report and believe his return at the head of a U.N. delegation will hinder" the U.N. role in Iraq, said al-Askari.
In the report, Brahimi said an early vote was not feasible, giving reasons long cited by Washington — no electoral structure, no reliable census and an untenable security situation.
At a news conference, al-Askari said: "His Eminence al-Sistani and many Shiites are unhappy with the report that the United Nations and Lakhdar Brahimi issued because it gives a lopsided picture of realities and facts, and paints a picture of a sectarian problem in Iraq."