Mitsubishi Heavy Industries Ltd. has offered to buy major U.S. nuclear power plant builder Westinghouse Electric Co. in a multibillion yen deal, company officials said Saturday.

The move is intended to increase Mitsubishi Heavy's profitability by tapping new fields to offset a squeeze in its bottom line brought on by cutbacks in public works spending in Japan, they said.

If successful, it would be the first large merger and acquisition deal for Mitsubishi Heavy, which is likely to form an alliance with some American firms to make a joint bid, the officials said.

The company hopes to sign a deal with Westinghouse, a wholly owned subsidiary of British Nuclear Fuels PLC, after reaching agreement on the terms of a contract, they said.

Other firms reportedly interested in acquiring Westinghouse include the Areva Group, a major French builder of nuclear reactors, General Electric Co., specializing in boiling-water reactor nuclear power plants, and a corporate acquisition fund.

Mitsubishi Heavy is said to be the favorite because it uses the same pressurized-water reactor design as Westinghouse's and because the two firms maintain close ties.

Westinghouse, based in the Pennsylvania city of Monroeville, built the world's first commercial nuclear power plant in 1957. It became a BNFL unit in 1999.