An aide to Muqtada al-Sadr says the Shiite cleric will agree to disband his Mahdi Army militia if ordered to do so by top Shiite clerics.

Hussein al-Zarqani, an al-Sadr aide currently in Iran, says al-Sadr will consult Grand Ayatollah Ali al-Sistani and other top Shiite clerics if the government continues to pressure him to disband the militia.

The decision came afrer Iraqi prime minister Nouri al-Malliki warned that al-Sadr would face political isolation if he failed to do so.

The Sadrists said Monday a move to ban them from elections would be unconstitutional.

The U.S. military, meanwhile, said two more soldiers died in roadside bombings Sunday, raising the day's American death toll to at least five. The announcement comes a day before the two top U.S. officials in Iraq are scheduled to brief Congress on prospects for the eventual withdrawal of American troops.

Gunbattles also continued Monday in Baghdad's main Shiite district of Sadr City, a day after fierce clashes broke out when some 1,000 U.S. and Iraqi troops began an operation to push deeper into the Mahdi Army's largest stronghold.

Al-Sadr plans to hold a "million-strong" anti-U.S. demonstration on Wednesday in Baghdad to protest the fifth anniversary of the capture of the Iraqi capital by invading U.S. troops.

With tensions rising, Prime Minister al-Maliki, himself a Shiite, told CNN Sunday that al-Sadr's followers would not be allowed "to participate in the political process or take part in upcoming elections unless they end the Mahdi Army."

He was referring to provincial elections expected in the fall that are likely to redistribute power in Iraq. The Sadrists have accused al-Maliki's government and rival parties of trying to diminish their standing ahead of the vote.

The prime minister, who took office in May 2006 with al-Sadr's support but later broke with the powerful cleric, had in the past repeatedly promised to disband militias but his comments on CNN were the first time he publicly singled out the Mahdi Army.

Senior Sadrist lawmaker Baha al-Aaraji called for calm but said the prime minister had no constitutional right to interfere with the elections.

"The Supreme Electoral Commission is the one to decide, not the prime minister, so the prime minister should not interfere in the work of this commission," al-Aaraji said Monday at a news conference.

He also called for a restructuring of government security institutions, saying any move to disband militias had to be applied to all political parties as well — a reference to the Badr Brigade of the Sadrists' main rival, the Supreme Islamic Iraqi Council, which dominates the Iraqi security forces.

"We say that we are with the law, but it has to be applied to all," al-Aaraji said during a news conference.

Lawmakers and officials involved in the effort to isolate the Sadrists politically have told The Associated Press that the first step would be adding language to a draft election bill banning parties that operate militias from fielding candidates in the provincial balloting due this fall. The government intends to send the draft to parliament within days and hopes to win approval within weeks, they said Sunday.

Such a move risks a violent backlash by the Mahdi Army. But if it succeeds, it could cause a major realignment of Iraq's political landscape.

The fighting in Sadr City has been the fiercest since al-Sadr ordered a cease-fire a week ago Sunday in a bid to restore calm amid growing anger over a government crackdown against militias in the southern Shiite city of Basra.

The cleric stopped short of asking his fighters to surrender their weapons, and sporadic clashes have continued as the Iraqi government issued a series of conflicting statements over how to deal with the militia.

Hospital officials said nine more people were killed, including five children and two women, and dozens wounded as gunbattles continued into Monday morning. That pushed the two-day death toll to at least 25.

Suspected Shiite militants also lobbed rockets and mortar shells into the U.S.-protected Green Zone and a military base elsewhere in Baghdad on Sunday, killing three American troops and wounding 31, officials said.

A roadside bomb killed a U.S. soldier Sunday in eastern Baghdad, the military said in a statement issued Monday. It did not specify the location but the area includes Sadr City and other predominantly Shiite neighborhoods.

Another American soldier was killed Sunday by a roadside bomb north of the capital in Diyala province, the military said separately. That raised to two the number of U.S. troops killed in that blast.

At least 4,020 members of the U.S. military have died since the Iraq war started in March 2003, according to an Associated Press count.

The inability of the Iraqi forces to curb the militias has cast doubt on their ability to take over their own security. The top American officials in Iraq — Gen. David Petraeus and Ambassador Ryan Crocker — are to start briefing Congress Tuesday on the prospects for further reductions in the U.S. troop presence in Iraq.

In his remarks, al-Maliki said he had a wide spectrum of political support for his efforts against the Mahdi Army.

"Solving the problem comes in no other way than dissolving the Mahdi Army," al-Maliki said. "We have opened the door for confrontation, a real confrontation with these gangs, and we will not stop until we are in full control of these areas."

But he acknowledged that Iraqi security forces faced obstacles but he said he was surprised the militia fighters had not mounted a fiercer response.

"Confronting the militias does still need more effort," he said. "Our readiness is not at full level yet, but what is happening in Sadr City is still less than what people expected the militias to do."