Iraq Again Faces Threat of U.S. Force : Mideast: U.N. inspectors unable to disable equipment at two missile-testing sites outside Baghdad. Libya and Iran also receive warnings.

WASHINGTON â€”  The Clinton Administration threatened to use military force to end a tense standoff between Iraq and the United Nations, while a team of U.N. inspectors failed Saturday in its mission to temporarily disable equipment at two missile-testing sites outside Baghdad.

In another round of U.S. saber rattling, Secretary of State Warren Christopher warned: “The situation is very serious. The use of force is entirely possible.�

Christopher also threatened new sanctions against Libya and Iran, raising the possibility that the United States would seek a worldwide freeze on Libyan assets for its refusal to turn over suspects in the 1988 bombing of Pan Am Flight 103 over Lockerbie, Scotland.

The new confrontation with Baghdad is the latest in a string of escalating disputes between the regime of Iraqi President Saddam Hussein and U.N. teams trying to enforce the requirement that Iraq destroy its weapons of mass destruction.

It arose after U.N. officials said Iraq refused to allow the installation of surveillance cameras in two testing sites outside Baghdad to ensure that Iraq does not attempt to manufacture long-range missiles.

The Iraqis have said they want to discuss a broad range of issues related to the 1991 cease-fire that ended the Persian Gulf War before allowing the cameras to be installed.

On Thursday, the United Nations decided to place seals on switches that operate the missile-testing equipment as a way of pressuring Baghdad into accepting the surveillance.

Mark Silver, the American heading the new team that arrived in Baghdad on Saturday, met with Iraqi officials for 90 minutes, but the Iraqis refused to permit the seals to be placed in the two plants.

An Iraqi close to the talks said, “The ball is back in the U.N. court,� but he refused to give details, the Associated Press reported from Baghdad.

Iraqi Information Minister Hamid Youssef Hammadi repeated to reporters in Amman, Jordan, on Saturday that Iraq will not permit the cameras to be installed until the United Nations reviews Baghdad’s compliance with the cease-fire agreement and possibly lifts sanctions that have blocked Iraq from selling oil or buying needed imports.

If Iraq ultimately refuses to permit U.N. monitoring or to dismantle the missile sites, Christopher said the United Nations will have to react, possibly with force.

“This isn’t just one violation,� he said from Tokyo on CNN’s “Evans and Novak� news show. “It is a pattern of violations that has to be taken into account.�

The threat of new military action comes barely two weeks after the United States fired a barrage of missiles at Iraq on June 27, damaging an intelligence center in Baghdad and killing a reported eight civilians in nearby homes. Washington said the action was in retaliation for an alleged Iraqi plot to assassinate former President George Bush during his trip to Kuwait last April. Iraq has denied any role in the foiled plot.

The secretary of state also had tough talk for Libya, which has refused to turn over suspects in the bombing of Pan American Flight 103, and for Iran, which the Administration accuses of sponsoring international terrorism and trying to acquire nuclear weapons. Possible actions against both countries were discussed at the seven-nation economic summit in Tokyo.

The United Nations is scheduled to review existing sanctions against Libya by Aug. 15. Christopher said tougher steps could be taken against Tripoli by the United States and its allies if the suspects are not turned over.

“There can be more oil-related sanctions and freezes of their (overseas) assets,� Christopher said.

Stronger steps against Libya, however, will require convincing some American allies that the damage would not rebound against them. The French and other European nations with economic ties to Libya have been reluctant to take tougher measures.