The Bush administration this week privately warned Iraq that Washington will hold Baghdad responsible for any terrorist attacks by pro-Iraqi terrorist groups against U.S. or allied targets and the Iraqi regime responded by accusing the United States of seeking a pretext for war.

U.S. officials also were seeking through unidentified third parties yesterday a clarification from Iran's revolutionary leadership of remarks by the country's spiritual leader calling for a "holy war" against the U.S. military presence in the Persian Gulf.

The officials said the U.S. message to Iran would reassure the Tehran government that the United States is not planning a long-term military presence in the Persian Gulf and would also seek to ascertain whether Tehran had changed its commitment to adhere to the U.N. trade embargo against Iraq.

Reports from Tehran have suggested that Iran might accept cargos of Iraqi crude oil as payment for food and medicine shipped to Iraq. After a decade of war and bitter estrangement, the two countries on Monday announced resumption of diplomatic relations.

In Baghdad, the U.S. diplomatic warning against Iraqi-inspired terrorism was issued Wednesday night by U.S. charge d'affaires Joseph C. Wilson IV to an Iraqi foreign ministry official. It followed a number of intelligence reports that pro-Iraqi terrorist organizations have been detected "casing" U.S. facilities and other potential targets in the Middle East, Europe, Latin America and Asia, U.S. officials said. These in turn have prompted two terrorism advisories to U.S. diplomatic missions worldwide.

The diplomatic message was made public yesterday by Iraq's deputy foreign minister and former ambassador to Washington, Nizar Hamdoon, who "categorically" denied in a statement to the Iraqi News Agency (INA) that the Baghdad regime was planning a terror campaign.

Last night, State Department spokesman Richard Boucher said the Iraqis were told "we would hold Iraq accountable for actions carried out by those who support or act on its behalf."

The Iraqi government said through INA that the U.S. warning had talked about holding Iraqi President Saddam Hussein personally responsible.

The news agency said the U.S. message "claimed that certain terrorist groups which have bases in Iraq and are supported by Iraq are preparing for attacks against targets of the United States and its friends."

The INA report said the U.S. message warned, "In the event of an attack of that sort, President Saddam Hussein should know that the United States will hold him personally responsible," the news agency reported.

It also added that the U.S. government "should expect" that its "crimes" against the Arab nation "will undoubtedly produce a natural reaction from the Arab and Islamic masses."

A State Department official yesterday said "we thought it prudent to raise the matter" of terrorist activity "directly with the Iraqis" and accordingly, Wilson delivered the oral message.

A department offficial, asked whether Wilson's message placed responsibility on Saddam personally for any terrorism, said, "We are not prepared to be precise on that point. Obviously, Saddam Hussein is in charge of the Iraqi government."

Boucher said during yesterday's noon State Department briefing, "We don't at this point have any specific and credible threats that we would be warning people against in specific terms, but our concerns have been made known."

Intelligence sources said police and counterintelligence agencies in a number of countries had spotted "Iraqi government" agents in some cases and, in other cases, had identified members of radical Palestinian terrorist groups that have allied themselves with Baghdad "casing" potential targets.

U.S. intelligence agencies also have been monitoring the steady buildup of international terrorists and Palestinian gunmen in Baghdad over several months, and some Western intelligence sources estimate that more than 1,000 terrorists and Palestinian militia fighters are now in the Iraqi capital or nearby military camps.

U.S. embassies in the Middle East and military officials and installations worldwide have received telephone bomb threats. One Air National Guard unit in the United States accepted a collect telephone call from a man speaking with a thick accent who threatened to blow up the entire unit, according to one counterterrorism report.

On Tuesday, the State Department said it had analyzed numerous threats to U.S. diplomatic and military facilities in "regions throughout the world."

"The U.S. remains concerned about indications that terrorist groups may be planning operations against U.S. nationals or interests in response to U.S. participation in the multinational effort to counter Saddam Hussein's aggression in Kuwait," the department said.

In the United States, the FBI has ordered a close watch on personnel of the Iraqi Embassy in Washington, the Iraqi mission to the United Nations in New York, Iraqi commercial interests, students and groups with ties to terrorist organizations.

"Obviously, any time there is a crisis, we look at defense of the home front," Oliver B. Revell, FBI associate executive director for investigations, said in a recent interview. "So we are taking all possible precautions against any element that might be supportive of Iraq in carrying out a terrorist operation against the United States."

As counterterrorism forces went to higher alert, Bush administration officials also worried yesterday whether Iran was preparing to shatter the international cooperation that has marked the trade embargo against Iraq.

Some U.S. officials said the initial U.S. belief is that a reconciliation seems unlikely between two countries that fought a bitter eight-year war. However, they added, if the two are moving toward friendly ties, Tehran for a price might help its old enemy evade the U.N. sanctions while at the same time inciting Shiite Moslems, who look to Iran for guidance, to engage in terrorism against American troops.

In what appeared to be an attempt to assure Iran that it has nothing to fear from the U.S. confrontation with Iraq, Boucher said the inflammatory remarks by Ayatollah Ali Khamenei appeared to be based on "a misunderstanding of what we mean by regional security structures and arrangements." That was a reference to Secretary of State James A. Baker III's Sept. 4 congressional testimony that the United States is considering some kind of regional alliance to coun- ter future security threats in the gulf.

"The United States has no intention of imposing itself, but rather of finding mutually acceptable arrangements which would help guarantee peace and prosperity," Boucher said. "Any such arrangements would have to fit regional realities."

Staff writer George Lardner Jr. contributed to this report.