The US Department of Justice has sued to block Hewlett Packard Enterprise’s $14 billion deal to acquire networking gear maker Juniper Networks, arguing that it would stifle competition, according to a complaint filed on Thursday.

The U.S. Justice Department has sued to block tech giant HPE from acquiring Juniper Networks, the networking firm, citing antitrust concerns.

Juniper Networks stock fell Thursday after the Justice Department moved to block a planned acquisition of the networking company by Hewlett Packard Enterprise.The Justice Department filed a complaint in California district court that seeks to block the merger on antitrust grounds.