A historic diamond necklace once owned by Egypt’s Queen Consort Nazli has been stolen from Vienna’s Museum of Applied Arts in a daytime smash-and-grab raid. Police are seeking two men who allegedly broke a display case with a hammer and fled with the piece, highlighting growing concern over high-profile thefts from European museums.

The platinum necklace contains 673 diamonds and totals about 200 carats; it was sold at Sotheby’s in 2015 for $4.3m. It was on loan for a Van Cleef & Arpels exhibition, which has been temporarily closed, and no one was injured; the theft follows recent museum raids across Europe, including the reported €88m Louvre crown-jewel robbery last October.