(Reuters) - The Amazon Labor Union (ALU) has agreed to affiliate with the International Brotherhood of Teamsters, one of the largest U.S. labor unions, in the latest sign that unionization efforts are picking up at the e-commerce giant.

ALU won a landmark victory in April 2022 after workers at Amazon's ( AMZN ) JFK8 facility, located in the New York City borough of Staten Island, voted to join the union, a first for the company in the United States.

The labor movement was driven by concerns over worker safety, including an alleged lack of protections for warehouse workers during the COVID-19 pandemic.

Teamsters General President Sean O'Brien announced the affiliation on Tuesday, during the union's general executive board meeting in Washington.

"Together we are creating an unstoppable movement to take on Amazon ( AMZN )," O'Brien said in a statement released on Wednesday.

"It will require unprecedented unity and long-term investment to finally force this company to respect working people and fairly negotiate."

Amazon ( AMZN ) did not immediately respond to Reuters' request for comment.

Teamsters said its board has unanimously approved the affiliation agreement. The ALU members will vote to ratify the agreement in the coming weeks.

If ratified, ALU will be a part of Teamsters' 1.3 million-member organization. The union will represent the roughly 8,000 Amazon ( AMZN ) warehouse workers at JFK8 and will have jurisdiction across New York's five boroughs, Teamsters said.