The main mixology bar at the Starbucks Reserve Roastery in Seattle. (GeekWire File Photo / Kurt Schlosser) Starbucks closed its flagship Reserve Roastery

Starbucks is permanently closing its Seattle Reserve Roastery, the company's first roastery, located on Capitol Hill.

Starbucks said on Thursday it would close underperforming stores in North America, including its iconic Seattle roastery, as CEO Brian Niccol presses ahead with his restructuring effort, which is expected to cost $1 billion in a bid to revive the company's flagging sales.

The Starbucks Reserve Roastery in Seattle's Capitol Hill neighborhood has closed, a move the company said is part of a broader plan that includes the closure of other North American coffeehouses and the elimination of hundreds of non-retail roles.

Starbucks announced it would close 1% of its corporate stores. Business Insider learned its flagship Reserve Roastery in Seattle is among them.

Starbucks plans to close 28 locations in Washington, including 10 in Seattle, as part of a company turnaround strategy.

The coffee giant's return-to-office mandate goes into effect on Monday, increasing the number of in-person days from three to four.

The Starbucks beneath the historic steaming kettle in Government Center is set to close, along with many others.