With no end in sight to the wave of kidnappings in Iraq, Turkey's main trucking association says it will stop carrying supplies to U.S. forces there. Ukraine's leader says he is cutting the number of troops in Iraq.

Iraq's top Muslim cleric, Ayatollah Ali al-Sistani, has condemned the bombing attacks on several Christian churches. From the Vatican Pope John Paul called the bombings "unjust aggression."

Interior Ministry spokesman Sabah Kadhim says the attacks could be the work of a group linked to al-Qaida operative Abu Musab Zarqawi.

"To me, I think the facts are, there were training camps in Afghanistan and, therefore, there are fully trained terrorists from throughout the Middle East, who are misled to believe that there is this fight between Christianity and Islam," he said.

The attacks have unnerved Iraq's small Christian minority that had so far escaped being targeted in the post-war violence.

The focus of terrorist violence these days has been foreign workers.

In a video on an Islamic website, a Turkish worker calls on other Turkish citizens not to work in Iraq. Then he is shot to death. A group linked to Jordanian-born terrorist Abu Musab al-Zarqawi claims responsibility for his kidnapping and execution.

The U.S. government has condemned the murder. State Department spokesman Adam Ereli calls it a "heinous and barbarous act."

"It shows the true nature of the terrorists holding this hostage. And it shows what they are about," Mr. Ereli said. "They're not about progress. They're not about working for the Iraqi people. They're about killing innocents and trying to impede progress toward stability and reconstruction and democracy in Iraq. "

The head of Turkey's main trucking association, which represents more than 30 trucking companies, says the security in Iraq is not safe enough to continue working there. But some business leaders have criticized the association for giving in to terrorist demands.

Some good news for Iraqi security forces: They were able to free a Lebanese hostage during a raid on a building where he was being held. The security forces also captured at least two of the kidnappers.

In other developments, U.S. forces in Iraq clashed with gunmen at the home of Shi'ite cleric Moqtada al-Sadr. The radical cleric led a two-month revolt against the U.S.-led occupation forces after his newspaper was closed and a close aide was arrested.

U.S. forces link Mr. al-Sadr to the murder last year of a moderate cleric in the holy city of Najaf. After the transfer of sovereignty in June, Iraq's interim leaders allowed Mr. al-Sadr to reopen his newspaper and postponed action on his arrest warrant.