Google is dramatically expanding its Washington offices and relocating them to within a couple of blocks of the U.S. Capitol.

The tech giant signed a lease for a 55,000-square-foot building at 25 Massachusetts Ave. NW. The building, owned by Republic Properties, is about a block from Union Station and gives Google about 25,000 more square feet than it has at its building at 1101 New York Ave. NW.

A company spokeswoman declined to comment on the new offices, including what they will be used for or when Google will move in.

“Google’s tenancy reinforces and validates the overall quality of our building and its place in the market,” Steven A. Grigg, president and chief executive of Republic Properties, said in a statement Wednesday.

Google is increasing its Washington footprint at a time when it is lobbying lawmakers on several issues. It has been pushing for a curb to what it calls frivolous lawsuits over patents. Google has also been trying to assure lawmakers that its Google Glass headset doesn’t violate privacy standards, even bringing sample headsets to members of Congress to give the device a test run.

The commercial real estate market in Washington has been weak overall. As government spending decreases, government contractors have moved to smaller offices. Law firms have been shrinking their footprint as well.

The technology sector is one of the few industries in the Washington area in which companies are growing and adding commercial space.

For example, Microsoft, which has government affairs offices — often used for product launches — at 901 K St. NW, is negotiating with D.C. government officials to open an innovation center on the east campus of St. Elizabeths Hospital, a 170-acre development site in Southeast Washington.

Doug Mueller, a broker for Jones Lang LaSalle who specializes in leasing space to tech companies, said the move was indicative of Google maturing. More-established firms often want to be on or near Capitol Hill, he said, while start-up firms and early-stage Internet companies gravitate to unique buildings near Chinatown.

Had Google remained in its New York Avenue space, it would have likely found itself across the street from an Apple store that many local commercial real estate insiders expect to open at CityCenterDC, a mixed-use space that is under construction.