A national conference considered a crucial first step in the country's fledgling move toward democracy was postponed for two weeks, an organizer said Thursday, a day after a massive car bombing that killed 70 people.

The conference had been due to start Saturday. But it has been plagued by difficulties before it even began.

Key political groups have been promising to boycott, leaders in ethnically diverse areas have been unable to agree on delegates to send — and even before Wednesday's car bombing, officials have expressed worries the gathering will be a target for terror attacks.

Abdul Halim al-Ruhaimi, one of the organizers, said that after U.N. requests, the Iraqis agreed to a postponement until mid-August to give officials time to speak with groups that had been reluctant to attend.

U.N. officials told The Associated Press they had repeatedly called on organizers to delay the conference for as long as a month to encourage wider participation and ensure it was properly prepared.

Al-Ruhaimi denied the suicide attack had any role in the decision to postpone the conference, which is to select a national assembly that will have some semi-parliamentary powers.

But the delay highlighted how Iraq's new government has struggled to get momentum in the democratic process even as violence has shown no sign of easing.

A wave of kidnappings continued — with the 22nd truck driver taken hostage by insurgents determined to hinder reconstruction and drive out coalition forces.

The insurgent group of Jordanian militant Abu Musab al-Zarqawi (search ) kidnapped the Somali truck driver and threatened to behead him in 48 hours if his Kuwaiti company doesn't stop working in Iraq, according to a videotape aired Thursday. The new abduction came a day after another militant group announced it had killed two Pakistani hostages.

Iraqi health officials, meanwhile, raised the death toll by two to 70 from Wednesday's suicide car blast, which devastated a busy, shop-filled street Wednesday in Baqouba. The bomb targeted Iraqi men waiting outside a police station to sign up for the force.

Also Thursday, an Iraqi official told Al-Jazeera television that deposed dictator Saddam Hussein (search ) suffers from a chronic prostate infection and has refused to have a biopsy to prove he does not have cancer. X-rays and blood tests did not show anything more serious than the prostate infection and the 67-year-old Saddam seemed to be in good health otherwise, despite rumors to the contrary, Iraqi Human Rights Minister Bakhtiar Amin said.

Also Thursday, the U.S. military said fighting between insurgents and American forces west of Baghdad killed two U.S. Marines. Both died in clashes Wednesday in Anbar province. The deaths raise to at least 908 the number of U.S. personnel killed in Iraq since the war began, according to an Associated Press tally.

A Polish soldier was killed and six wounded when a series of roadside bombs set off by remote control went off Thursday and showered their patrol with shrapnel on a road south of Baghdad, the Polish Defense Ministry said.

Poland sent troops in support of the U.S.-led invasion of Iraq and now commands some 6,200 forces from 16 countries in south-central Iraq, including 2,400 of its own.

Iraqi Prime Minister Ayad Allawi (search ) said Thursday that Muslim must close ranks against "those gangs, those terrorists and those criminals" who he said are threatening the Arab world. He said that if the 15-month old insurgency in Iraq prevails, countries such as Saudi Arabia, Syria and Lebanon would not be safe.

With Secretary of State Colin Powell (search ) standing at his side during talks in the Saudi city of Jiddah, Allawi voiced support for a Saudi-led initiative under which Muslim countries would be encouraged to contribute to a new force that would try to bring stability to Iraq.

"The leaders of this region must unify and must stand as one group," Allawi told a news conference.

Ukraine, meanwhile, is planning to reduce and eventually pull out its 1,650 troops from Iraq — the fourth largest non-U.S. contingent in the country.

The war has long been unpopular in Ukraine, and the government faces upcoming elections. The soldiers' mandate was up for renewal in August, and President Leonid Kuchma (search ) had previously suggested that they would remain.

A Defense Ministry spokesman, Vyacheslav Bolotniuk, said Ukraine is negogiating its plans with the United States and Poland, but he gave no timeline, saying only, "There will be a decrease of troops."

News of the latest hostage drama in Iraq followed Wednesday's announcement by a militant group calling itself the Islamic Army in Iraq that it had killed two Pakistani hostages because Pakistan was considering sending troops to the region.

Pakistan's leaders and parliament on Thursday condemned the apparent killings, while the slain men's grieving families pleaded with their killers to release the bodies for proper burial.

"Those who have committed this crime have caused the greatest harm both to humanity and Islam," Pakistani President Gen. Pervez Musharraf (search ) said Thursday.