BAGHDAD, June 9 (Reuters) - Iraq took delivery on Monday of several ancient artefacts seized by U.S. customs officers in Philadelphia after being looted from Baghdad's national museum during the U.S.-led invasion in 2003.

At a ceremony in Baghdad, Iraq's foreign minister, Hoshiyar Zebari, handed over the recovered relics to the country's antiquities minister, Mohammed al-Uraibi.

Nestled in a protective foam casing inside a small square box were 11 cylinder seals made from agate and alabaster. They once hung around the necks of important men of state and were used to affix their personal stamps to documents.

"We are standing before antiques that belong to 2,000 and 3,000 BC," said Amira Iidan, head of Iraq's antiquities and heritage office, pointing out several dating from Babylonian times.

Antiquities Ministry spokesman Abdul-Zahra al-Talagani said the artefacts were found in the U.S. city of Philadelphia by customs officials last month and handed over to the Iraqi embassy in Washington. He did not know the circumstances of their discovery.

Thousands of antiquities in Iraq, often referred to as the cradle of civilisation, were looted in the aftermath of the U.S. invasion. Iraqi officials have blamed the pilfering on organised smugglers and occupying foreign troops.

Many of the artefacts were stolen from the national museum in Baghdad, but many thousands more from the estimated 10,000 poorly guarded archaeological sites scattered around Iraq, which has been home to many cultures over the centuries.

Iraq is now trying to reclaim the artefacts, a number of which have turned up at art auctions around the globe.

In April, Syria returned about 700 stolen artefacts, including gold coins and jewellery that had been seized by its customs officers.

"This is only the start. We hope to return more of these pieces in the near future," said foreign minister Zebari.

Antiquities Minister Uraibi said some 15,000 items had been stolen during the wholesale looting of the national museum in 2003, of which 5,000-6,000 had been returned.

"We have 1,600 pieces in Jordan. We will return them soon with the help of the minister of foreign affairs. There are also others in Gulf countries and in Europe," he said. (Writing by Ross Colvin; editing by Keith Weir)