Updated

Iraqi militants said Saturday they kidnapped two Turks and threatened to behead them within 48 hours, the latest in the country's unrelenting wave of abductions, even as efforts intensified to free seven truck drivers taken captive by other insurgents.

The Tawhid and Jihad group of Jordanian militant Abu Musab al-Zarqawi (search) demanded the Turks' employers leave Iraq in a videotape aired on Al-Jazeera (search) television, which showed three masked, black-garbed gunmen standing behind two seated men holding various forms of identification, including what apparently were Turkish passports.

Al-Jazeera identified the men as two Turkish truck drivers working for a Turkish company delivering goods to U.S. forces in Iraq. The network said the militants threatened to decapitate the men if their demands were not met.

An official at the Turkish Embassy (search) in Baghdad, speaking on condition of anonymity, said he saw the tape's broadcast but had no further details on the men's capture. The tape did not indicate when exactly the 48-hour period ends.

Militants loyal to al-Zarqawi have claimed responsibility for a number of bloody attacks and beheadings of previous foreign hostages, including U.S. businessman Nicholas Berg, South Korean translator Kim Sun-il and Bulgarian truck driver Georgi Lazov.

In Fallujah, west of Baghdad, huge explosions were heard late Saturday as fighting resumed between U.S. forces and Iraqi insurgents. Men bellowed through mosque speakers for doctors to go to hospitals and people to donate blood for the injured.

In central Baghdad, a roadside bomb killed two people, a man and a woman, and wounded two others on Sunday. Police said all were civilians.

In another abduction, a Lebanese citizen was snatched in Baghdad early Saturday, a Lebanese Foreign Ministry official told The Associated Press on condition of anonymity. The official said no contact had been made with the kidnappers and had no further details.

The victim's Iraqi driver, who also was snatched but later released, identified the Lebanese man as Vlado Abu Ghadi, director of the Lara construction company.

More than 70 foreigners have been kidnapped by insurgents in recent months in a campaign aimed at pushing out international troops and companies backing U.S. troops and reconstruction efforts. Many have been videotaped and paraded on TV screens surrounded by armed, masked men demanding their countries withdraw.

Mediators and officials expressed optimism Saturday for the release of seven hostages -- three Indians, three Kenyans and an Egyptian -- held since July 21. An official from the drivers' Kuwait employer met tribal leaders acting as mediators to craft an offer to their captors, and India sent its ambassador to Oman, Talmiz Ahmed, to Iraq to help in the negotiations.

The kidnappers have threatened to kill one of the hostages if their employer, Kuwait and Gulf Link Transport Co., fails to meet their demands, including ending their work in Iraq.

The group, which calls itself "The Holders of the Black Banners," had said they would carry out their threat by Friday night, but they extended their deadlines repeatedly and appeared to have done so again.

Mahdi Saleh, an official from the Kuwaiti company, arrived here Saturday for talks with Sheik Hisham al-Duleimi, who runs an organization of tribal leaders trying to negotiate the hostages' release.

Speaking to Al-Arabiya TV on Saturday, al-Duleimi said he expected the militant group to extend its deadline for executing a hostage until Sunday because negotiations were progressing well.

"We are in the final stages of the negotiations to release the hostages ... and, God willing, we will be able to save the necks of those seven hostages," al-Duleimi said.

Al-Duleimi's spokesman, Muqam al-Hamadani, told the AP his group planned to craft an offer with the Kuwaiti company before announcing it publicly. He expected the kidnappers to respond by releasing another video to the media, which has been their primary form of communication.

Ram Murti, father of one Indian hostage, Antaryami, told the AP in New Delhi that the Indian prime minister's office had phoned him saying the government had received "positive" feedback from Iraq. He did not elaborate.

Meanwhile, Turkish driver Mehmet Dayar, abducted in Iraq on July 17, was freed in Mosul, northern Iraq, after promising his captors not to return, his niece Jihan Dayar told the AP.

Dayar spent 12 days in captivity before returning Thursday to his hometown of Cizre, near the Turkish border with Iraq, she said.

In other violence, gunmen shot and killed Ismail al-Kilabi, the head of the state-run Mamoudiyah Teachers Institute, after a mosque prayer service Friday, police Lt. Ala'a Hussein said Saturday.

Al-Kilabi had ignored militants' warnings to stop working for Iraqi authorities after the U.S.-led coalition transferred power to the country's interim government last month, Hussein said.

Huge explosions were heard in Fallujah as U.S. forces tried to re-enter the volatile town. Witnesses said militants and U.S. troops clashed in Fallujah's main street and helicopters fired up to eight rockets into an industrial area.

Dr. Osama Abdel Rahman, of Fallujah Hospital, said one Iraqi was killed and seven others, including a child, were injured.

An official at another hospital, Dr. Hammadi al-Duleimi, said his medical center treated 12 wounded people.

Earlier Saturday, the U.S. military said 20 insurgents were killed during clashes in Fallujah late Thursday and early Friday. Hospital officials said 13 Iraqis, mainly women and children, died and 14 were injured. The U.S. military and Iraqi security forces suffered no casualties.

Meanwhile, an official from the Karbala office of firebrand Shiite cleric Muqtada al-Sadr's movement said U.S. forces on Saturday arrested Methal al-Husseini, the office head.

The official, who spoke on condition of anonymity, claimed U.S. forces detained al-Husseini at his house in Hindeiyah, 12 miles east of Karbala, a southern Iraqi city.

U.S. and Polish military officials, who control the region, declined to confirm the report.