Jacobs Engineering Group Inc. said Tuesday that it has acquired a 60 percent interest in Saudi Arabian firm Zamal & Turbag Consulting Engineers. Financial terms of the deal were not disclosed.

“Oil and gas, refining and chemical project activities are increasing worldwide and especially in the Middle East,” said Craig Martin, the chief executive of the Pasadena-based engineering services provider. “We are excited about our investment in Zamal & Turbag because it brings their established local talent into our network.”

The combination of Zamal & Turbag with Jacobs’ existing operations in Saudi Arabia brings the total number of staff in the region to more than 500, Jacobs said in a release.

Shares in Jacobs were up 5.8 percent to $73.91 in early trading Tuesday on the New York Stock Exchange.