Amazon broke ground Tuesday ( 28 May )on a Seaport office it will open in 2021 and home at least 2,000 employees in fields such as machine learning, speech science, and robotics.

Governor Charlie Baker and Mayor Martin J. Walsh joined Amazon executives to market a 17-story, 525,000-square-foot construction in Seaport Square. Amazon has leased all of the building’s office space, with a choice to rent a second similar construction that’s been approved next door, as the e-commerce giant expands its so-called technology hub in Boston.

Amazon said it wouldn’t seek one location for the 25,000 employees it had intended for Queens but instead will”continue to hire and grow across our 17 corporate offices and tech hubs” — of that Boston is one.

Mike Touloumtzis, the engineer that leads Amazon’s local tech offices, on Tuesday repeatedly, pointed into the region’s highly educated people for a reason. “Amazon is investing millions in Massachusetts and the Greater Boston area because of the exceptionally talented workforce that exists here,” he said.

Amazon will get $5 million in municipal tax breaks if it hires 2,000 employees and $10 million if it hires 4,000 by renting a second Seaport Square construction. Touloumtzis said the firm employs about 4,500 in Massachusetts.

Just this past year, Amazon opened a smaller office in Fort Point, about a 5-minute walk in the building that broke ground on Tuesday. Additionally, it has offices in Back Bay and Kendall Square.

Amazon hasn’t decided whether to lease the other construction at Seaport Square, Touloumtzis stated but continues to expand its technology workforce here, filling a brand new 900-person office on nearby Melcher Street at Fort Point and preserving its significant presence in Kendall Square in Cambridge.

Even though a variety of other big tech companies are hiring quickly in Boston, Touloumtzis stated, Amazon has had little trouble finding workers.

“We think this is a great place to be,” he explained.