HAYWARD — An Amazon unit has leased a big data center building in Hayward that is currently under construction, a fresh indicator of the tech behemoth’s widening Bay Area expansion.

Amazon Data Services, a subsidiary of Amazon, has leased a building at 25800 Clawiter Road in Hayward, according to documents filed on Feb. 4 with the Alameda County Recorder’s Office.

The three-story building will total 278,500 square feet when it is complete, documents filed with Hayward city planners show.

The project was under construction in recent days, this news organization’s visit to the development site showed. Work was being conducted on the exterior of the building.

The project is being developed by an affiliate that is jointly controlled by Houston-based Hines, a major real estate developer with a global reach; and the New Jersey-based global investments unit of MetLife, an insurance and financial services titan.

The county documents show that while Amazon has leased the building, the tech company also has a right of first offer for the property, according to the county documents.

The arrangement means that Amazon Data Services has a right to make the first offer to purchase the building in case the current site owners, Hines and MetLife, seek to sell the property.

The data center is part of a four-building complex known as Clawiter Road Industrial Project that’s near the interchange of Highway 92 and Clawiter Road.

The overall project totals 615,600 square feet, according to the Hayward planning documents, and would sprout on 26 acres at 25800 and 25858 Clawiter Road.

The data center was the only building undergoing vertical construction at the project site, the recent observation of the property shows.

The data center building that Amazon leased in Hayward occupies approximately 6.6 acres.

A few miles away, at 2710 W. Winton Ave. in Hayward, Amazon has leased a big chunk of space for a logistics center.

Amazon Data Services has been an active player in real estate elsewhere in the Bay Area.

In January, Amazon Data Services paid $51.8 million for a seven-acre parcel at 2315 Mission College Blvd. in Santa Clara in an all-cash deal.

In the East Bay, Amazon has bought or leased an array of buildings and land sites.

Amazon’s East Bay sites include properties in Oakland, Pleasanton, Livermore, Hayward, Richmond and Oakley.