The Vatican has returned three fragments of the Parthenon sculptures to Greece in a move that has been described as a "gesture of friendship".

The decision to return the 2,500-year-old marbles was announced by Pope Francis last year.

One is a chunk of a horses head, the other a bearded man and the third a head of a boy.

Greece hopes the move will spur other overseas institutions that hold Parthenon sculptures to return them.

About 50% of the Parthenon's original sculptures have survived and almost half of them are in the British Museum.

"The ceremony today... similar to the gesture by the government of Sicily and the Republic of Italy a few months ago, shows the road that we could follow, that everyone could follow, in order for the unity of the Parthenon to be restored," Greece's culture minister Linda Mendoni said on Friday.

As the marbles were returned, dignitaries exchanged hand shakes and smiled in front of the cameras, including the leader of the Greek Orthodox Church, Archbishop Ieronymos.

"My personal heartfelt wish is that this initiative is mimicked by others. Pope Francis showed that this is possible and significant," he said.

The marbles had been in the papal collection and Vatican Museums for centuries.

But Greece has been trying to recover them from the Vatican and other European collections since the beginning of the 20th century.

In the early 1800s dozens of marbles were taken from Greece's Parthenon on the orders of Scottish nobleman Thomas Bruce, known as Lord Elgin.

He then sold the marbles to the British government, who then displayed them in the British Museum.

Reports have suggested the British Museum's chairman, George Osborne, is close to agreeing a deal with Greece.

In January, the then UK culture secretary Michele Donelan said that the sculptures "belong here" in Britain.

The British Museum is prevented by law from permanently returning the artworks to Greece.

But there was speculation that a deal could involve the sculptures heading to Athens on loan in rotation, in return for classical objects that have never been seen outside Greece before.