"An unknown suspect broke through a hallway wall into the apartment and removed artwork, watches and other jewelry. A video recorder attached to surveillance cameras inside the apartment also was taken," police said in a statement, Reuters reported.

The stolen works are Warhol's "Superman," "The Truck" and the eight-piece signed set of prints called "Camouflage," the Lichtenstein prints titled, "Thinking Nude" and "Moonscape," and a Carl Fudge oil painting, "Live Cat." Warhol's "Superman" print is part of his 1980s "Myths" series featuring fictional characters with mass-cultural appeal, including Mickey Mouse and Uncle Sam.

Along with stolen Rolex and Cartier watches and jewelry, the take was worth about $750,000 according to media reports.

The thief or thieves bypassed several security measures to get into the five-story building, with just one elevator that is key-operated elevator, the New York Post reported.

The building has a nightclub in the basement, a cafe on the first floor and a restaurant on the second flood. A key is required to get out of the elevator at the third-floor apartment of Romanoff, 49, the Post said. A staircase does not extend to the third floor, making it a mystery how thieves got to the art.

Romanoff is part of a beef empire that began as a store opened by his Russian immigrant relatives in 1905. He's president of Nebraska Meat Corp. of New Jersey, one of the nation's largest distributors of smoked meat,

The Romanoff home is in a neighborhood filled with old warehouses and meatpacking companies now turned into retail and living space, restaurants and boutiques.

Police say the thief drilled a hole through the wall of a hallway sometime between Nov. 24 and 28.

Lichtenstein, who died in 1997, created "Thinking Nude" in 1994, one of 40 limited-edition works that are part of his "Nudes" series based on comic-book illustrations. A similar print recently sold for about $85,000 at Christie's, according to the auction house's website.

Warhol's "Camouflage" prints were done in 1986, a year before he died, AP said, and Lichtenstein created "Thinking Nude" in 1994, three years before he died.