Thousands of workers at Amazon facilities across the United States went on strike Thursday, the Teamsters Union said, halting work at the height of the busy holiday gift-giving season.

The union, which says it represents some 10,000 workers at the massive online retailer's facilities around the country, called the action the "largest strike against Amazon in US history".

Workers will picket at facilities in New York, Atlanta, southern California, San Francisco and Illinois, with other Amazon Teamsters "prepared to join them," the union said in a statement.

"The nationwide action follows Amazon's repeated refusal to follow the law and bargain with the thousands of Amazon workers who organised with the Teamsters," it said.

Less than a week before the Christmas holiday, the strike threatens a significant disruption of deliveries of Amazon orders as Americans rush to send last-minute gifts.

"If your package is delayed during the holidays, you can blame Amazon’s insatiable greed," Teamsters boss Sean O'Brien said in the statement.

"We gave Amazon a clear deadline to come to the table and do right by our members. They ignored it."

Workers at a New York facility became the first Amazon employees to unionize in April 2022, with several other sites since following suit.

Originally an independent union, the Amazon workers voted in June to affiliate with the Teamsters.

Amazon has repeatedly sought to block the unionization efforts, with legal proceedings still ongoing.

The Teamsters represent only a tiny fraction of the 1.5 million employees at Amazon, the nation's second-largest private employer after Walmart.

The union has some 1.3 million members nationwide in sectors ranging from freight delivery to cafeteria employees.

In the 2024 presidential election, the union chose not to endorse either Donald Trump or Kamala Harris, the first time it did not back the Democratic nominee since 2000.