A homicide bomber killed 30 Iraqis at an army recruiting center Wednesday and lawmakers rushed back to Baghdad for a special session of parliament to vote on a last-minute compromise to gain Sunni support on the draft constitution.

The lawmakers were summoned after Shiite, Sunni Arab and Kurdish powerbrokers reached the breakthrough on the charter, reviving hopes of winning Sunni approval of the document in Saturday's nationwide referendum.

The suicide attacker set off explosives hidden beneath his clothing at the first of two checkpoints outside the recruiting center in Tal Afar (search), where men were gathering to apply for jobs, said army Capt. Raad Ahmed and town police chief Brig. Najim Abdullah. They said at least 30 people were killed and 35 wounded.

The small town was struck Tuesday by another homicide bomber who killed 30 civilians and wounded 45 when he plowed his explosives-packed vehicle into a crowded outdoor market. Al Qaeda in Iraq claimed responsibility for that attack.

In August, U.S. and Iraqi forces conducted a major offensive in Tal Afar, 93 miles east of the Syrian border, claiming to have killed 200 insurgents and driven many others out.

In other violence Wednesday, three homicide car bombs, two roadside blasts and two drive-by shootings killed three Iraqis and wounded 28 in Baghdad and the northwestern city of Baqouba, police said.

An explosion set by insurgents also shut down an oil pipeline from the northern city of Kirkuk to refineries in Beiji (search), an official said. The pipeline is open only intermittently because of incessant sabotage.

In Baghdad, Saad Naif al-Hardan (search), Iraq's minister of provincial affairs, escaped an apparent assassination attempt when a convoy of cars preparing to pick him up at his office was hit by a suicide car bomb that wounded five bodyguards and five bystanders, police said.

The bodies of eight Iraqis who apparently had been kidnapped were found Wednesday in Baghdad and Iskandariyah (search), 30 miles south of the capital, police said.

Those and other attacks raised the death toll in the last 17 days to 431 in the militants' campaign to thwart Saturday's constitutional referendum, even as President Jalal Talabani (search) and other politicians praised the last-minute breakthrough as "historic" and urged the charter's approval.

"There is no excuse for Arab Sunnis to boycott the vote now that we have responded to all their demands and suggestions," Talabani said at a nationally televised news conference.

He was followed by other politicians who also hailed the development, including National Assembly Speaker Hajim al-Hassani (search), a Sunni; Vice President Ghazi al-Yawer (search), a Sunni; former Prime Minister Ayad Allawi (search), a Shiite; and Abdul Aziz al-Hakim (search), a Shiite who heads the Iraqi United Alliance, the largest coalition in parliament.

However, 19 small Sunni-led parties, including the National Dialogue Council, criticized the compromise and again urged a "no" vote Saturday.

The National Assembly could have trouble forming a quorum for the Wednesday evening session to vote on the final version of the constitution incorporating the last-minute agreements.

A monthlong legislative recess began Monday, and many lawmakers returned to their provinces for the referendum and to mark the holy month of Ramadan (search) with their families.

For security reasons, a four-day national curfew begins Thursday, with a holiday on Saturday.

If a quorum is reached, the vote could simply be a formality, since most lawmakers generally follow their party leaders.

Parliament failed to reach a quorum earlier this week when it met to try to strip former Defense Minister Hazem Shaalan (search) of immunity from prosecution over the alleged disappearance or misappropriation of $1 billion in military procurement funds.

The draft constitution already has been printed by the United Nations and millions of copies are being distributed to voters. Any new additions probably would have to be announced in the media.

After negotiators reached the compromise, at least one Sunni Arab party said it would urge its followers to approve the charter.

Under the deal, the two sides agreed on a mechanism to consider amending the constitution after it is approved in the nationwide vote. The next parliament, to be formed after Dec. 15 elections, will set up a commission within four months to consider amendments.

The amendments later would have to be approved by the entire parliament and submitted to another referendum two months later.

That is no guarantee, however, that Sunnis will be able to make the changes they seek. They are likely to have a stronger representation in the next parliament but still would face a strong Shiite and Kurdish majority that likely would oppose major changes.

The deal also does not make it any easier for Sunnis to push through amendments, only guaranteeing them the opportunity to try.

Any changes apparently would have to be approved by a two-thirds majority in the parliament — just as is outlined in the constitution — before they can go to a referendum.

"The important principle here is that this provides an assurance [to Sunnis] that this constitution is not the end of history but is subject to amendment," said Ridha Jawad Taqi of the Supreme Council of the Islamic Revolution in Iraq (search), a top Shiite party in the government.

Sunnis fear that the draft constitution as it stands will fragment Iraq because it allows Shiites and Kurds to create mini-states in the oil-rich north and south, leaving Sunnis in a poor central zone.

Majority Shiite and Kurdish leaders support the draft constitution, and the United States has been eager to see it approved to avert more political turmoil, delaying plans to start a withdrawal of U.S. forces.

U.S. officials had pushed the three days of negotiations between Shiite and Kurdish leaders in the government and Sunni Arab officials. They concluded with marathon talks at Talabani's house.

A top Sunni negotiator, Ayad al-Samarraie of the Iraqi Islamic Party (search), said the measure would allow it to "stop the campaign rejecting the constitution and we will call on Sunni Arabs to vote yes."

But other major Sunni parties were not at the talks, and at least one senior Sunni leader, Saleh al-Mutlaq, said he was not yet convinced.

"The Islamic party was participating alone in these negotiations and making its own decisions," al-Mutlaq said. "This is strange because the Iraqi Islamic party does not represent all the Sunni Arabs but only a small percentage of them."

The announcement was the first break in the ranks of Sunni Arab leaders and will likely undermine the campaign to defeat the constitution at the polls.

That possibility was evident Wednesday, when the Association of Muslim Scholars (search), an influential Sunni group that has called for a boycott in the referendum, seemed to be reconsidering that position.

"After the National Assembly's special session, we will make our decision," said Mohammad Bashar al-Faidhi, the group's founder. "Generally speaking, our position is to boycott the whole political process, but if something positive comes out of the session, then we might think in another way."