WASHINGTON/KABUL - The Pentagon said on Wednesday it had launched an inquiry into whether a U.S. special forces raid had killed anti-Taliban fighters by mistake, while Iraq, Iran and North Korea rejected President George W. Bush's charge they form an "axis of evil" in his war against terrorism.

In a chilling development, the group that claims it has kidnapped Wall Street Journal reporter Daniel Pearl in Pakistan sent e-mail to news organizations threatening to kill him within 24 hours unless the U.S. government released Pakistani prisoners held in the Afghan war. It warned other U.S. journalists in Pakistan to leave within three days.

Pakistani police detained a chief justice and a deputy foreign minister of the vanquished Taliban near Quetta and arrested a dozen people linked to a radical Islamic group near Islamabad in the search for Pearl.

With lawlessness threatening to undermine his fledgling government, interim Afghan leader Hamid Karzai urged the United Nations to expand an international force providing security in the capital Kabul, saying security around the country was vital for peace and economic recovery in his shattered nation.

In an emotional visit to "ground zero" where New York's World Trade Center twin towers once stood, Karzai laid a wreath and pledged to hunt down those responsible for the Sept. 11 attacks on the United States which killed more than 3,000 people.

"We want the people of New York to see the face of these people on trial on TV and to see they will receive justice," said Karzai, wearing his trademark blue and green striped cape and Afghan hat. "That we will do. That is a promise," he said.

The whereabouts of Saudi-born militant Osama bin Laden, Washington's chief suspect in the attacks, remained a mystery. It was not even known whether he or his ally, Taliban leader Mullah Mohammad Omar, were still alive.

Since Sept. 11, extremist groups appear to be increasing their search for weapons that could destroy large populations such as chemical, biological, radiological and nuclear, said a new unclassified CIA report to Congress released on Wednesday.

"Terrorist groups are most interested in chemicals such as cyanide salts to contaminate food and water supplies or to assassinate individuals," the report said.

Iran, Iraq and North Korea all rejected the accusation made by Bush in his first State of the Union address on Tuesday night that they formed an "axis of evil" developing weapons of mass destruction to threaten America and the world.

In a later clarification, the White House said Bush "is not sending a signal that military action is imminent" against the three countries.

White House spokesman Ari Fleischer said Bush's use of the phrase "axis of evil" was "more rhetorical than historical" and not a link between these countries and the World War Two alliance among Germany, Japan and Italy, known as the Axis.

Iran said Bush's remarks smacked of a desire for hegemony, Iraq suggested they presaged a U.S. attack on Baghdad and North Korea saw them as evidence of a "policy of aggression."

In Baghdad, a senior Iraqi parliamentarian said Bush was laying the groundwork for another U.S. assault on Iraq, whose troops were driven from Kuwait in 1991 by a coalition led by his father, former president George Bush.

The Pentagon decision to investigate last week's raid came after officials originally dismissed reports of a botched raid that killed supporters of Karzai's government, saying the mission had killed 15 Taliban fighters, destroyed an arms cache and took more than two dozen captives.

Afghan security sources in Kandahar gave details of what they said was an erroneous attack. "The commander, Abdul Qadoos, was killed along with 17 other people when U.S. troops attacked the district of Kharz in Uruzgan province last week," one of the sources told Reuters.

Abdul Qadoos had fought against the Taliban in its Kandahar stronghold, and he had been on his way from the Uruzgan provincial capital, Tarin Kot, to Kharz to collect weapons. It was an official mission to bring peace to the area, they said.

"They were also going to talk to local people as part of our campaign to persuade people to disarm, and to come over to the government side," one source said.

Most residents in Kharz were from the Pashtun tribe of Achakzais, and the sources said they believed the Americans were misled for one side or another to gain the upper hand in one of the feuds that plague Pashtun society.

"Look, we want the Americans here. We fought with them side-by-side against the Taliban. But we ask them -- please, please, don't make this mistake again," one source said.

Defense Secretary Donald Rumsfeld said the investigation of the special forces raid was ordered by Army Gen. Tommy Franks, head of the U.S. Central Command with responsibility for the Afghan military campaign.

"It is perfectly possible that you could go in a situation, get shot at, shoot back and end up having someone say that those people were Taliban," Rumsfeld told reporters. "And (have) somebody else say that those people were people we were engaging in our local government. And both can be true in as confused a situation as it is in village after village in Afghanistan."

"I don't think there's any sense on our part that we've done something wrong. It is that when there are allegations, you've got to go run it to ground," added Air Force Gen. Richard Myers, chairman of the Pentagon Joint Chiefs of Staff, at a news briefing.

It is not the first time that U.S. intelligence gathering has been called into question. When a delegation heading to Kabul in December for the inauguration of the new government reached a village in the eastern province of Paktia, elders said it was repeatedly attacked by U.S. aircraft. They said dozens of people were killed, many of them women and children.

There were fresh reports of conflict in Afghanistan.

Fighting erupted between rival tribal factions east of the Afghan town of Gardez, which is patrolled by U.S. forces, while to the west about 300 Taliban and al Qaeda fighters gathered for an imminent attack on the municipality, a local official said. He said the Americans were aware of the threat.

Abdul Wali, a member of the Gardez tribal council, said the clash was between one faction that backs the town governor, Padshah Kahan Zadran, and another faction opposed to him. Wali said there were no casualties in the fighting.

"Basically, these people oppose the appointment of (Zadran) as the governor and want to create trouble," Wali told Reuters by telephone. "They are supported by Taliban and al Qaeda."

U.S. forces in the area were not involved in the dispute but had been trying to determine what was going on, he said.

Wali said al Qaeda and Taliban forces had gathered to the west, in the Shahi Koot region of Zormat district, and were preparing to launch an assault on the town.

"They have light and heavy weapons and have a plan to attack Gardez," he said, adding that top Taliban commander Jalaluddin Haqqani was massing the forces and planned an "imminent" offensive.

Following Bush's warning that his war on terrorism had only just started with the Afghanistan campaign, joint exercises between U.S. and Philippine forces to fight Muslim extremists will start on Thursday.

About 600 U.S. soldiers are to take part in the exercises which represent the most significant expansion of the U.S. war on terror after Afghanistan.

The Philippines has long battled Islamic militants in the south and one group, Abu Sayyaf, suspected by the United States of having links to al Qaeda, will be a focus of the training exercises in the former U.S. colony. Nampa-Reuters