MADRID (AP) — A Stradivarius cello housed at the Spanish Royal Palace was broken in an accident, an official said Monday. The instrument could be worth more than $20 million.

A National Heritage official declined to specify what went wrong. She refused to comment on an El Mundo newspaper report that the instrument fell off a table during a photo session. She confirmed it happened about three weeks ago. The official spoke on condition of anonymity in line with department policy.

The damage sustained: a piece that joins the neck of the 17th-century instrument to the body of it broke and fell off the rest of the cello. That piece was not original but rather a replacement installed in the 19th century.

The official said the cello can and will be repaired.

The heritage official declined to say how much the cello was worth. She said it was part of a set of instruments — two violins and a viola were the others — that were known as “the Quartet.” They got this name because they were commissioned at the same time.

However, Tim Ingles, head of the musical instrument department at Sotheby’s auction house in London, said he believed the Spanish cello was worth $20 million (€15.4 million) or more.

This made me sick to my stomach when I first heard it.