Powell told reporters he had given the message to Kuwaiti Foreign Minister Mohammed al-Sabah on behalf of President George W. Bush, his administration and military planners.

"Kuwait understood the threat and was willing to step forward," he said. "We're deeply appreciative of all they have done."

"Without that support, I'm not sure the operation could have been conducted," Powell said as the foreign minister stood beside him outside the State Department.

Kuwait served as the main launch pad for the US-led invasion of Iraq, hosting more than 170,000 US and British troops.

Iraq invaded Kuwait in 1990 sparking the first Gulf War and al Sabah said his country was pleased to see that Saddam Hussein had been toppled.

"I expressed today Kuwait's appreciation for the work that the United States is doing in liberating the Iraqi people from their ordeal," he said.

The minister added that Kuwait still urgently wanted to find nearly 600 of its countrymen it believes have been held captive since 1991 and called for "more intense cooperation" to locate them.

"One out of every thousand Kuwaiti is still unaccounted for in Iraq and this something that the secretary has indicated the United States is most concerned about," he said.

"We agreed to expedite and strengthen our cooperation on this issue," he added.

Neither Powell nor the minister could confirm reports that some Kuwaiti prisoners had been found in an underground bunker in Baghdad.

Kuwait says 605 people disappeared during Baghdad's occupation of the emirate in 1990-1991 and believes many were kept in Iraqi jails.

US Defense Secretary Donald Rumsfeld pledged Monday to help Kuwait locate the missing prisoners. He also appealed to Iraqis to "provide any information that they may have so we can achieve or goal of returning all those individuals."

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