More than 600 looted artifacts that were retrieved by the United States, shipped back to Iraq, and then mysteriously lost finally have been found in the prime minister's warehouse alongside boxes of kitchen supplies, the Iraqi tourism minister said Monday.

The ancient pieces – including clay pots, a bronze Sumerian figurine, and stone tablets etched with cuneiform writing – were returned to the Iraqi National Museum, resolving a real-life caper that began when many of them were stolen from a museum in the northern Iraqi city of Kirkuk in 1991.

US authorities had recovered the pieces over several years, some of which had been put up for auction. In December 2008, Gen. David Petraeus, who was then the commander of American forces in Iraq, had arranged to have them transported to Iraq on a military plane.

It should have been a happy moment for Iraq, which had seen tens of thousands of artifacts from one of the world's most ancient civilizations plundered during the 1990s and after the 2003 US-led invasion, and had been working hard to get them back.

What followed instead was an embarrassing mistake, official negligence, or some combination of the two.

The US military delivered the pieces, packed in about a dozen boxes, to Prime Minister Nouri al-Maliki's office, American and Iraqi officials said. Somehow, the boxes were sent to Mr. Maliki's official storage facility, where they sat for nearly two years and apparently were forgotten.

Earlier this month, Iraq's ambassador to the United States, Samir Sumaidaie, who'd arranged for the pieces to be shipped back in 2008, attended the unveiling of several hundred other retrieved artifacts at the museum in Baghdad. Mr. Sumaidaie said that he was trying find out what happened after Maliki's office received the pieces.

The comments were interpreted as putting pressure on an unresponsive prime minister to account for the works, and they appear to have worked.

Maliki formed a committee to look into the matter, and tourism officials announced Sunday that they'd found the 638 pieces.

"We went to the warehouse and we found these boxes," said the minister for tourism and antiquities, Qahtan al-Jubouri. "They didn't know what was inside them."

When he was asked whether anyone would be called to account for the blunder, Mr. Jubouri demurred. Maliki's office has remained silent on the matter.

The most important piece in the boxes, museum officials said, was a bronze statue credited to the Sumerians, inhabitants of southern Mesopotamia, in about 5,000 B.C. An American archeological expedition discovered the figurine in 1968.

Although security remains extremely fragile in Baghdad, officials said they planned to reopen the museum as early as the end of the year.

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