ATHENS, Greece — A long-delayed new museum in Athens where Greece hopes to reunite its ancient Acropolis masterpieces with Britain's Elgin Marbles will open in September, officials said.

Culture Minister Michalis Liapis said finishing the glass and concrete building was a "national challenge" and would boost Greece's campaign to wrest the 5th century B.C. sculptures from the British Museum.

"We will inaugurate the new museum in September," he said. "This modern, functional and safe museum will be a strong argument against those who oppose the Marbles' return."

The Elgin Marbles — or Parthenon Sculptures — were removed from the Parthenon temple by Scottish diplomat Lord Elgin in the 19th century, when Greece was still an unwilling part of the Ottoman empire. The London museum has repeatedly rejected Greek calls for their return.

Liapis said a delicate operation to transfer hundreds of priceless statues and thousands of smaller pieces from the old museum on top of the Acropolis hill to the new building would be finished by the end of March.

The $190 million museum was initially scheduled for completion in 2004, but was delayed by legal wrangles and archaeological discoveries on the central Athens plot — at the foot of the Acropolis.

Museum director Dimitris Pantermalis said the focal point of the exhibition, sculptures from the Parthenon that escaped removal to Britain and other European countries, would soon be placed in its final position in a glass hall at the top of the building.

"In a few weeks we will complete the trial installation of copies. which will help us resolve all issues regarding the display, and will then replace them with the originals," he said.

The Parthenon was built between 447-432 B.C. in honor of Athena, ancient Athens' patron goddess, and was decorated with hundreds of sculpted figures of gods and participants in a religious procession. About half of the surviving works are now in London.

Designed by U.S.-based architect Bernard Tschumi in collaboration with Greece's Michalis Photiadis, the new Acropolis museum will contain more than 4,000 works, 10 times the number on display in the old museum.