CITY OF INDUSTRY, Calif. (KABC) — Workers at three Southern California Amazon facilities joined thousands of others in a nationwide strike against Amazon Thursday amid the busy holiday shipping season.

The Teamsters union said they launched a strike after Amazon ignored the deadline for contract negotiations on Dec. 15.

Teamster workers walked off the job at 6 a.m. Thursday at delivery hubs in City of Industry, Palmdale, and Victorville. The Teamsters union also represents workers in San Bernardino.

The strike extends all the way to the East Coast, affecting facilities in New York, Illinois and Georgia.

The union is calling it the largest strike against the online shopping giant less than a week before Christmas.

“If your package is delayed during the holidays, you can blame Amazon’s insatiable greed. We gave Amazon a clear deadline to come to the table and do right by our members. They ignored it,” said Teamsters General President Sean M. O’Brien. “These greedy executives had every chance to show decency and respect for the people who make their obscene profits possible. Instead, they’ve pushed workers to the limit and now they’re paying the price. This strike is on them.”

In a statement to ABC News, an Amazon spokesperson claimed that most of the strikers are not Amazon employees.

“What you see here are almost entirely outsiders-not Amazon employees or partners-and the suggestion otherwise is just another lie from the Teamsters. The truth is that they were unable to get enough support from our employees and partners and have brought in outsiders to come and harass and intimidate our team, which is inappropriate and dangerous. We appreciate all our team’s great work to serve their customers and communities, and are continuing to focus on getting customers their holiday orders.”

CNN Wire contributed to this report.