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.

The Justice Department on Thursday sued to block Hewlett Packard Enterprise from buying Juniper Networks for $14 billion. Why it matters: This is the first antitrust case filed by the Trump administration,

Read about Hewlett Packard Enterprise and Juniper Networks' response to a Justice Department move to block the proposed $14 billion all-cash acquisition deal between the companies.