Franka Bruns, Associated Press
A visitor views Pablo Picasso's painting "Boy Leading a Horse." It is one of two Picassos at the center of an ownership controversy.

NEW YORK — The two Picasso paintings have been in prominent New York museum collections for decades. But now the institutions are asking a court to declare them the lawful owners amid a Jewish scholar's claims that the works were the rightful property of a relative persecuted in Nazi Germany.

The Museum of Modern Art and the Solomon R. Guggenheim Foundation said they took the step Friday to fend off an expected lawsuit from Julius H. Schoeps, a German who has been waging a legal fight to recover artwork and property once owned by his great-uncle.

Schoeps demanded on Nov. 1 that the museums hand over "Boy Leading a Horse," which is in MoMA's collection, and "Le Moulin de la Galette," in the Guggenheim's collection.

MoMA Director Glenn D. Lowry and Guggenheim Foundation Director Thomas Krens said they are confident the paintings were not obtained under Nazi duress.

"The Museum of Modern Art and the Guggenheim Museum take the issue of restitution very seriously," they said in a joint statement. "Evidence from our extensive research makes clear the museums' ownership of these works and also makes clear that Mr. Schoeps has no basis for his claim."

Schoeps' lawyer, John J. Byrne, declined to comment on the museums' suit, filed in U.S. District Court in Manhattan.

Both paintings were originally owned by Paul von Mendelssohn-Bartholdy, an aristocratic German banker and descendent of the composer Felix Mendelssohn. Mendelssohn-Bartholdy died in 1935, two years after Hitler came to power.

Before his death, Mendelssohn-Bartholdy engaged in a series of maneuvers that Schoeps said were intended to protect his estate and an incredible art collection. Besides the Picassos, it included nine paintings by Vincent van Gogh.

The family sold the two paintings at issue in the lawsuit to the Jewish art dealer Justin Thannhauser in 1934 or 1935. Thannhauser fled Germany and spent much of the war in Switzerland. He kept "Le Moulin de la Galette" until 1963, when he gave it to the Guggenheim museum. He sold "Boy Leading a Horse" to former MoMA chairman William Paley in 1936. Paley gave it to MoMA in 1964, according to the museum's Web site.

Schoeps' attempts to reclaim the works have not gone well.

He filed a federal lawsuit in 2006 attempting to stop Picasso's "Portrait de Angel Fernandez de Soto" from being auctioned off, but a judge threw out the case for lack of jurisdiction.

An identical claim was tossed last month by a state judge in New York. The judge said Schoeps hadn't yet taken the proper legal steps to have himself declared the rightful heir to the Mendelssohn-Bartholdy estate.

Christie's auction house predicted "Portrait de Angel Fernandez de Soto," also known as "The Absinthe Drinker," could sell for $60 million.