BAGHDAD, Iraq — Iraq's interim prime minister blamed the U.S.-led coalition Tuesday for "great negligence" in the ambush that killed about 50 soldiers heading home after graduation from a U.S.-run training course, and warned of an escalation of terrorist attacks.
Underscoring the warning, insurgents made a new threat of nationwide attacks against U.S. and Iraqi forces "with weapons and military tactics they have not experienced before" if American forces try to storm the militant stronghold of Fallujah.
Video posted on a militant Islamic Web site in the name of Abu Musab al-Zarqawi's group also showed what it claimed was a Japanese captive and threatened to behead him within 48 hours unless Japan pulls its troops from Iraq. Japanese Prime Minister Junichiro Koizumi rejected the demand.
"I won't withdraw troops," he was quoted as saying by Japan's Kyodo news agency after receiving news of the hostage threat.
Prime Minister Ayad Allawi told the Iraqi National Council, a government oversight body, that coalition forces' negligent handling of security was responsible for Saturday's deadly ambush along a remote highway near the Iranian border.
"It was a heinous crime where a group of National Guardsmen were targeted," Allawi said. "There was great negligence on the part of some coalition forces."
He said the Defense Ministry began an investigation into whether insurgents had infiltrated military ranks to obtain information about troop movements.
Allawi did not explain how the coalition had failed in its responsibilities to the Iraqi troops, who were traveling to southern Iraq in three buses after graduating from a training course at the Kirkush military camp northeast of Baghdad. The buses had no armed escort and the soldiers were not carrying weapons.
However, in an interview with Al-Arabiya television, Defense Minister Hazem Shaalan blamed the recruits, who in their eagerness to get home decided to leave immediately after their graduation and take an unauthorized route.
"They are to blame. They graduated at 12 p.m. and could have delayed their trip," he said. Shaalan added that neither the Defense Ministry, the Kirkush commanders nor the U.S.-run forces were to blame.
"They are the ones who chose this road that led them to this ugly result," he said of the victims. "There might have been some people who gave information about them to hostile sides."
Some of the bodies were found in rows — shot execution-style through the head — at a site about 95 miles east of Baghdad, the Defense Ministry said. Other bodies were found on a burned bus nearby.
The U.S. command did not respond directly to Allawi's comments but said in a statement: "This was a cold-blooded and systematic massacre by terrorists. They and no one else, must be held fully accountable for these heinous acts."
In his appearance before the council, Allawi also warned that insurgents were massing in Fallujah, 40 miles west of Baghdad, and "you should expect an escalation in terrorist acts."
"Our information confirms that more extremists have entered Fallujah lately to try to harm the residents of Fallujah and then harm the Iraqi government by keeping the situation volatile," he said. "The enemies are becoming aware that if Iraq recovers, it will be a major blow to them and therefore they will escalate terrorist acts and activities."
Allawi has told Fallujah leaders that they must surrender extremists, chief among them al-Zarqawi, or face attack. His comments Tuesday appeared aimed at preparing Iraqis for the eventuality of such an attack, which could inflame public opinion in Iraq and elsewhere in the Arab world.
In a videotape obtained by Associated Press Television News, militants calling themselves the "factions of the Islamic Resistance Movement in Iraq" warned that if the Americans try to overrun Fallujah, "we swear in the name of God that all armed factions will attack all military and civilian targets of the occupation forces and the interim government."
The warning was delivered by a masked gunman dressed in an old-style Iraqi army uniform, flanked by seven other men. The speaker accused the Iraqi government of "aborting a peaceful solution with the people of Fallujah."
"We will attack them with weapons and military tactics they have not experienced before and in the ways and forms of our choosing," he added.
He warned all Iraqi military personnel and government employees to quit their jobs; otherwise they "will be permissible targets for our fighters." A banner behind him read "The Movement of Iraqi National Resistance Regiments."
Daily insurgent attacks across the country have taken a heavy toll on Iraqis, and attacks have increased by 25 percent in the two weeks since the holy Muslim month of Ramadan began.
Interior Minister Falah Hassan al-Naqib said that 92 car bomb attacks occurred from June through September, killing 569 people and wounding 1,318.
Iraqi officials said in August there were a record 645 attacks against "public or state institutions," that killed 147 and wounded 385. In September, the number of attacks dropped to 120, but the number of casualties remained high: 193 dead and 385 injured.
Al-Zarqawi's followers have claimed responsibility for the beheadings of foreign hostages and numerous attacks, including Saturday's ambush on Iraqi recruits.
The new kidnapping claim, which could not immediately be verified, was the second Iraqi kidnapping crisis to hit Japan and poses a new test to Koizumi's government, which has dispatched 500 troops on a humanitarian mission in support of U.S.-led reconstruction efforts in Iraq despite strong opposition in public opinion.
The man, who had long hair and wore a white T-shirt, was identified only as someone connected to the Japanese armed forces. He spoke briefly in halting English and Japanese, addressing himself to Koizumi.
"Mr. Koizumi. They seek the withdrawal of Japanese Self-Defense Forces... (and say they) will take my head off. I'm sorry. I want to return to Japan again," he said. The video's authenticity could not be independently confirmed.
When the captive finished speaking, the video showed him kneeling before three masked militants. One of them read a statement.
"We give the Japanese government 48 hours to withdraw its troops from Iraq, otherwise his fate will be the same of that his predecessors, Berg and Bigley and other infidels," the man said, referring to the beheadings of British engineer Kenneth Bigley and U.S. businessman Nicholas Berg.
The video, which lasted just under three minutes, bore the logo of al-Qaida in Iraq, the new name for al-Zarqawi's group, which was previously known as Tawhid and Jihad.
Insurgents in Iraq have kidnapped more than 150 foreigners. Most were kidnapped for ransom and freed unharmed, but at least 30 have been killed as part of a campaign to drive out foreign troops and companies.
U.S. forces recently have ratcheted up their aerial and artillery assaults against Fallujah, using precision airstrikes to destroy safe houses, command centers, and weapons storage belonging to al-Zarqawi's network. An aide to al-Zarqawi was killed during an overnight strike, the U.S. military said.