The Justice Department sued to block Hewlett Packard Enterprise's $14 billion acquisition of rival Juniper Networks on Thursday, the first attempt to stop a merger by a new Trump administration that is expected to take a softer approach to mergers.

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.

DOJ cited reduced competition in the wireless market as the biggest problem with the proposed $14 billion sale of Juniper Networks to Hewlett Packard Enterprise. The vendors say they plan to “vigorously defend the transaction in court.