BAGHDAD—The United States is returning more than 17,000 ancient artifacts looted and smuggled out of Iraq after the U.S. invasion in 2003, including a 3,500-year-old clay tablet bearing part of the Epic of Gilgamesh, Iraq said on Tuesday. Tens of thousands of antiquities disappeared from Iraq after the 2003 invasion that toppled leader Saddam Hussein. Many more were smuggled or destroyed by the iconoclastic ISIS terrorist group, which held a third of Iraq between 2014 and 2017 before it was defeated by Iraqi and international forces. U.S. authorities working to recover the artifacts recently reached an agreement with Baghdad to return items seized from dealers and museums in the United States, the Iraqi culture and foreign ministries said. “The U.S. government seized some of the artifacts and sent them to the [Iraqi] embassy. The Gilgamesh tablet, the important one, will be returned to Iraq in the next month after legal …