Liberty Property Trust on Monday announced the sale of four fully-leased Malvern office buildings encompassing 568,658 square feet of space for $173.1 million, another step in the Wayne-based trust's shift to focus on owning warehouses.

So far this year, Liberty has taken in $742.4 million from the sale of office buildings, it said.

The latest sales are at: 50 Morehall Road, 117,000 square feet; 60 Morehall Road, 117,000 square feet; 425 Old Morehall Road, 201,658 square feet; and 1001 Cedar Hollow Road, 133,000 square feet, Liberty said.

The Vanguard Group leases at least some of the buildings.

Liberty is getting out of the business of developing and owning office buildings after a decades-long string of high-profile projects that have come to define Philadelphia's skyline — including One Liberty Place and Comcast Corp.'s two skyscrapers.

The company's current office holdings include stakes in the Comcast Center and Comcast Technology Center along Arch Street in Center City, the Penn Medicine office building at 800 Walnut St., and 10 office and research buildings at the Navy Yard. It also owns acres on the Camden waterfront that it acquired with plans to develop for office and other uses.

All will be sold, with the proceeds being reinvested into Liberty's portfolio of industrial properties, which now span 24 U.S. markets as well as the United Kingdom, and count Amazon.com Inc. as their top tenant.