The U.S. Justice Department has filed suit to block Hewlett Packard Enterprise Co.’s proposed acquisition of Juniper Networks Inc. for $14 billion. Officials submitted the complaint today to the U.S. District Court for the Northern District of California.

WASHINGTON—The Justice Department on Thursday sued to block the tie-up of Hewlett Packard Enterprise and Juniper Networks, a $14 billion deal that would join the second-largest and third-largest providers of wireless networking solutions for large corporate customers.