NEW YORK (AFP).- A US museum has extended indefinitely a $10 million reward for the recovery of 13 works of art, including priceless Rembrandts and a Vermeer, stolen three decades ago.

Last May, the Isabella Stewart Gardner Museum doubled to $10 million a long-standing reward for information leading to the recovery of all 13 works in good condition, hoping that a deadline of December 31, 2017 would concentrate minds.

The institution said it was the largest private reward in the world at that time and continues to identify the 1990 theft as "the largest art heist in history."

The stolen art includes three Rembrandts, a Vermeer, and five sketches and watercolors by Degas, together estimated to be worth more than half a billion dollars.

"The strategy generated some very good leads that continue to be pursued," the museum said Thursday, announcing that the board of trustees had voted to extend the reward.

"We hope anyone with knowledge that might further our work will come forward," said Anthony Amore, the museum's director of security.

"Typically stolen masterpieces are either recovered soon after a theft or a generation later," he added. "We remain optimistic that these works will ultimately be recovered."

Thieves dressed as police officers walked into the museum in the early hours of March 18, 1990 and stole the 13 works of art in 81 minutes, after handcuffing and tying up two security guards in the basement.

Last year's record-breaking auction of Leonardo da Vinci's "Salvator Mundi" for $450 million in New York is believed to have made the missing masterpieces only more valuable.


© Agence France-Presse