July 2 (Reuters) - The U.S. Federal Trade Commission said on Tuesday it will sue to block the $4 billion merger between mattress manufacturer Tempur Sealy International Inc and retailer Mattress Firm.

Tempur Sealy had announced the cash-and-stock deal in May 2023, seeking to add Mattress Firm's more than 2,300 brick-and-mortar store locations. The combined company would have about 3,000 stores globally. (Reporting by Jody Godoy)