LOS ANGELES, JAN. 21 -- Philanthropist Armand Hammer announced today that he will build a $30 million private art museum to house his three art collections worth more than $250 million.

The decision angered and disappointed officials of the Los Angeles County Museum of Art, because Hammer for years had said he would leave his collection to their museum.

Hammer, 89, chairman and chief executive officer of Occidental Petroleum, said the museum will be built alongside Occidental's headquarters in Westwood, 10 miles west of downtown Los Angeles. It will be open to the public.

"I have always said that I plan to leave these collections for the enjoyment of the people of Los Angeles and with the construction of this new art museum and cultural center, that will be assured," Hammer said.

Daniel Belin, chairman of the county museum board, reacted angrily. "Dr. Hammer has for 15 years said publicly that he was going to leave his collection to the county Museum of Art," he said. "I'm not talking legality, but this is a breach of a moral commitment."

Belin said the museum has over the years passed up some works in the belief it would inherit the Hammer collection.

The Armand Hammer Museum of Art and Cultural Center will house the extensive artworks that Hammer began accumulating in the Soviet Union nearly a half-century ago.

Included are a collection of 126 works by Dutch, Flemish, German and Italian masters; a codex, or book of notes and drawings, by Leonardo da Vinci; and more than 10,000 lithographs, paintings and other objects by the 19th-century French artist Honore' Daumier.

Most of the works are owned by the private Armand Hammer Foundation, which has exhibited them throughout the United States and abroad for 20 years.

The Hammer museum will join two other major private museums founded by industrialists in the region: the J. Paul Getty Museum in Malibu and the Norton Simon Museum in Pasadena.