Aecom Technology Corp., a downtown Los Angeles provider of technical and management support services, said late Thursday that it acquired a Pittsburgh logistics and management firm.

SSI Services Inc., which provides facility operations, maintenance and management support to government clients, was acquired from a private Pittsburgh technical services firm named Vanadium Group for an undisclosed amount.

“SSI is very well respected within the industry for its comprehensive critical-mission support operations,” Chief Executive John M. Dionisio said in a statement. “The addition of SSI security experts to the Aecom team greatly enhances our ability to meet our clients’ needs in this specialty area globally.”

Separately, Aecom announced it had won contracts worth $60 million from the Hong Kong Special Administrative Region to provide infrastructure design and construction supervision consulting services for a project to build commercial, social and recreational facilities at a former airport.

Aecom shares were down 60 cents, or 2 percent, to $25.30 in midday trading on the New York Stock Exchange.