Amazon.com Inc. workers at the company’s sole unionized warehouse in the US joined a broader strike by the International Brotherhood of Teamsters.

The union is aiming to pressure the online retailer by threatening delays in package deliveries during the critical holiday season.

A spokesperson for Amazon said the union claims they represent “thousands of Amazon employees and drivers” when they don’t.

Union organizers have called an end to a five-day strike against Amazon by about 100 Atlanta drivers who joined other workers around the country

The Staten Island Amazon facility, known as JFK8, employs more than 5,000 workers, and about 100 of them joined the picket line early Saturday.

Bundled up and huddled around propane and diesel heaters, the group appeared upbeat and optimistic as strike organizers provided them with hats, jackets, hand warmers, beverages and snacks.

The Teamsters said the strike will begin Thursday at several facilities, including in New York City, Atlanta, California and Illinois.

The International Brotherhood of Teamsters said workers at seven Amazon facilities will begin a strike on Thursday morning.

Striking Amazon and Starbucks workers in California and elsewhere have long pushed for union contracts. The Trump administration is unlikely to be on their side. Story from @CalMatters.org.

In labor news, Amazon is facing accusations it attempted to flood the picket line of striking workers in Queens, New York. On Saturday, water began gushing from an Amazon building close to where striking workers had gathered.

The agency also has opened or settled hundreds of charges against Amazon. On Thursday, a day before the Starbucks walkouts, the Teamsters union announced strikes at seven Amazon delivery hubs. Starbucks did not immediately reply to a request for comment.