Amazon will increase pay between 50 cents and $3 an hour for half a million workers in its warehouses, delivery network and other fulfillment teams, the company said on Wednesday.

The action follows scrutiny of Amazon from lawmakers and an unsuccessful unionization push that ended this month at its large warehouse in Alabama. In 2018, Amazon raised its minimum pay to $15 an hour. In recent months, it has publicly campaigned to raise the federal minimum to $15, too.

Amazon has been on a hiring spree during the pandemic. As more customers ordered items online, the company added 400,000 employees in the United States last year. Its total work force stands at almost 1.3 million people.

Amazon typically revaluates wages each fall, before the holiday shopping season. But this year, it moved those changes earlier, said Darcie Henry, an Amazon vice president of people experience and technology. The new wages will roll out from mid-May through early June. Ms. Henry said the company was hiring for “tens of thousands” of open positions.

Jeff Bezos, Amazon’s founder and chief executive, recently told shareholders in his annual letter that he recognized the company needed “a better vision for how we create value for employees — a vision for their success.” He said that Amazon had always striven to be “Earth’s Most Customer-Centric Company,” and that now he wanted it to be “Earth’s Best Employer and Earth’s Safest Place to Work” as well.

Amazon is scheduled to report quarterly earnings on Thursday.