After Iraq's interim prime minister issued a "final call" to militants in Najaf to disarm and vacate the holy Imam Ali Shrine, radical cleric Muqtada al-Sadr (search) on Thursday told his followers to hand control of the shrine to Shiite religious authorities, according to an aide.

Aws al-Khafaji, a top aide to the cleric, told the pan-Arab Al-Jazeera television station that al-Sadr asked his armed supporters to cede the Imam Ali Shrine compound to the office of Grand Ayatollah Ali al-Sistani (search), the top Shiite cleric in Iraq.

"I call on the religious authority again to receive the shrine so that it won't be taken by the hands of the enemy and of treason. I have offered it to you before and you have refused before the (latest) incidents," read a letter al-Sadr reportedly sent to his followers, as shown on Al-Arabiya television. The seal of al-Sadr's office was on the letter, but his signature was not, according to the station.

But the cleric refused to dissolve his fighting force. The letter contended the militia belonged to Imam Mahdi (search), the Shiite messiah.

"Let everyone know that this army is the Imam Mahdi's base, and I have no right to ever disband it," the letter said.

It also rejected any political role for al-Sadr's followers.

"I will never take part in any political work as along as the occupation is there. I will continue, all my life, to build Iraq, its freedom, independence and liberation," the letter said.

Iraqi Prime Minister Iyad Allawi (search) said earlier Thursday that the Iraqi military would rout the militiamen out of the compound if al-Sadr failed to heed his ultimatum.

Late Thursday, at least 30 explosions shook the Old City section of Najaf (search). The blasts may have come from U.S. warplanes, which were in the skies over the holy city. Gunbattles also persisted throughout the day.

The holy city has been wracked by violence since the Shiite militant uprising began two weeks ago. The U.S. military says the Najaf clashes have killed hundreds of militants, though the militants deny that. Nine U.S. troops and at least 40 Iraqi police have been killed as well.

Seven officers died Thursday when a mortar barrage slammed into a police station Thursday, wounding 31 others.

The police station has been the frequent target of attacks from militants loyal to al-Sadr. Some of the wounded were forced to sit on the hospital floor as others lined the halls. Blood pooled on the floor and moans of pain echoed in the corridors.

After the attack, Iraqi police raided a local hotel where foreign journalists were staying, claiming they suspected some of the reporters helped the attackers locate the police station.

Shortly before the mortar attack, al-Sadr's spokesman said the peace deal offered by the fledgling Iraqi government was unacceptable.

"It is very clear that we reject them," Sheikh Ahmed al-Sheibani, a senior al-Sadr aide and Mahdi Army commander, told reporters. The aide spoke from inside the shrine where about 3,000 of al-Sadr's fighters and supporters are holed up.

'Martyrdom or Victory'

An official in the cleric's office, Haidar al-Tourfi, said he received a text message from al-Sadr saying: "Either martyrdom or victory."

But Allawi said that's not an option.

Al-Sadr must now appear in person and put in writing a commitment to disarm and leave Najaf, Allawi said Thursday. That way, the cleric and his loyalists will receive protection from the government and he may stand in the Iraqi election as a candidate if he wishes to influence Iraqi policy, Allawi said.

"This is the final call to them to disarm, vacate the holy shrine, engage in political work, and to consider the interests of the homeland above the factional and personal ones," Allawi told a press conference in Baghdad.

Allawi also reiterated the government's position that it would not negotiate with armed militias.

On Wednesday, al-Sadr sent a letter to the Iraqi National Conference saying he agreed to their peace demands and that his fighters would lay down their arms and leave the shrine.

By Thursday, Iraqi officials were getting fed up with the firebrand cleric and his antics and vowed that an attack could be imminent within hours.

Iraqi Minister of State Qassim Dawoud said that to prevent such an attack, al-Sadr must immediately disarm his Mahdi Army militia and hand over its weapons to the authorities. He also must sign a statement saying he will refrain from future violence and release all civilians and Iraqi security forces his militants have kidnapped. In addition, al-Sadr must hold a news conference to announce he is disbanding the Mahdi Army.

An al-Sadr representative in Baghdad, Abdel-Hadi al-Darraji, warned that fighting in Najaf could "ignite a revolution all over Iraq."

"We welcome any initiative to stop the bloodbath in Najaf," he told Al-Arabiya television. "Otherwise the battle will move to Baghdad, Amarah, Basra and anywhere in Iraq."

The Arab League chief on Thursday called for an immediate end to military operations in Najaf and said Iraqi civilians must be spared from the violence. Secretary-General Amr Moussa received news of artillery "shelling and renewed clashes (in Najaf) with great uneasiness," Arab League spokesman Hossam Zaki said in a statement.

Holding Al-Sadr's Feet to the Fire

There's also word there could also be a split among al-Sadr's army but there was no confirmation of that.

"This also could be a game," terrorism analyst Walid Phares told FOX News. "He put himself in a position where he cannot negotiate — he rejected everything" the Iraqis offered and maybe a supposed split among his ranks is a ploy.

"I think he's losing [clout] with the Iraqi people, I think they're fed up with this," said Robert Jordan, a former U.S. ambassador to Saudi Arabia.

Phares said while it's possible for the U.S.-backed Iraqi forces to beat al-Sadr, "the problem is not the military dimension, it is what will happen after."

Moderate clerics need to convince the Iraqi people that al-Sadr is not representative of the Shiite population and need to make sure the cleric's loyalists don't participate in retribution against those rooting for al-Sadr's ousting, Phares added.

Sen. Saxby Chambliss, R-Ga., told FOX News that finally going after al-Sadr final is necessary for a stable Iraq.

"This guy has gone back and forth and every time he's backed down, it's to regroup his forces," Chambliss said. "It's time we held his feet to the fire — he is the menace over there that's been holding things up."

In Washington, the Bush administration said al-Sadr needed to match words with deeds.

"We have seen many, many times al-Sadr assume or say he is going to accept certain terms and then it turns out not to be the case," said National Security Adviser Condoleezza Rice.

As clashes in Najaf continued, Arab television station Al-Jazeera aired a video Thursday showing a militant group that called itself the Martyrs Brigade vowing to kill missing Western journalist Micah Garen if U.S. forces do not leave Najaf within 48 hours.

In Other Violence

U.S. forces and Shiite insurgents also fought in the Baghdad slum of Sadr City, where more than 50 militants and civilians were killed Thursday, Mahdi Army spokesman Na'eem al-Kaabi said.

U.S. tanks moved throughout the streets of the impoverished Baghdad neighborhood on Thursday, and helicopter gunships shot at militants from the skies.

Elsewhere in Iraq:

— Several other loud explosions rattled central Baghdad, sending at least one plume of black smoke into the sky.

-- The military said an American base in Najaf came under mortar attack early Thursday, but no casualties were reported.

— U.S. Marines also conducted raids in three parts of Kufa, just east of Najaf. The military said "close air support" was called in.

— One soldier died when attackers fired on a U.S. patrol Wednesday in the east Baghdad neighborhood of Sadr City. Another was killed while patrolling the same area hours earlier.

— Two Marines from the 1st Marine Expeditionary Force were killed Wednesday; one died while conducting "security and stability operations" in Najaf, and the other died in a vehicle accident in Anbar province west of Baghdad.

— In Hillah, two Polish troops were killed and five were injured early Thursday in a car crash that followed an ambush by insurgents.

— Unidentified attackers killed an Iraqi security officer working for the state-run Northern Oil Co., on Thursday. Two other security officers were injured in the attack.

The Associated Press contributed to this report.