More than 220 pieces — including jewelry and enameled objects worth about $5 million — stolen from Russia's famed State Hermitage Museum were not insured, officials said Tuesday.

The theft is believed to have been an inside job that probably took place over several years, the museum's director, Mikhail Piotrovsky, told reporters a day after reporting the thefts.

"It is clear that without the involvement of museum staff, this could not have happened," he said.

CountryWatch: Russia

The theft, which highlights the poor security at Russian cultural institutions, was discovered after a routine inventory check that began in October 2005 and was completed at the end of July.

The 221 missing items included a selection of medieval and 19th-century Russian jewelry, silverware and enameled objects. Piotrovsky said the items were not insured because they were in storage; only exhibited artworks at the Hermitage are insured.

Years can pass between inventory checks of specific collections in the more than 1,000-room museum with more than 3 million pieces of artwork, he said.

The curator in charge of most of the collection where the theft occurred died suddenly at her workplace when the inventory check began in October. The museum did not identify the curator or say how she died.

The head of the federal agency in charge of preserving Russia's cultural heritage said the theft was a sign of the inadequate security at museums and other facilities housing cultural treasures.

Russia's state funding for culture dried up after the 1991 Soviet collapse, and cultural institutions have been plagued by chronic money woes, with frequent reports of theft.

Piotrovsky said that only several hundred thousand of the 3 million artworks at the Hermitage are registered in an electronic catalogue, and the museum spends only $750,000 a year on security.

The Hermitage, housed in the Russian czars' ornate Winter Palace along St. Petersburg's Neva River, was started by Catherine the Great in 1764.

Its vast holdings of antiquities, decorative art and Western art include world-renowned collections of Italian Renaissance, 17th- and 18th-century Dutch and Flemish, and Impressionist paintings.