(Reuters) - Starbucks ( SBUX ) held contract negotiations with the Workers United union over a two-day session in Atlanta, both the parties said on Friday, with plans to meet again in late May.

The coffee chain and Workers United, that represents Starbucks ( SBUX ) workers in the United States, began negotiations this week on what they called a "foundational framework" to guide union organizing and collective bargaining across the country.

Workers at more than 420 of Starbucks' ( SBUX ) 9,000 U.S. stores have voted to unionize since 2021.

"We discussed a broad range of topics, including ... details relating to the union's representation of partners as both sides worked on the foundational framework that will contribute to single-store contract negotiations and ratification," Starbucks ( SBUX ) and the union said in a joint statement on Friday.