Nvidia’s $40 billion acquisition of British chip designer Arm Holdings is in trouble. The United Kingdom announced it would intervene in the deal on national security grounds, Bloomberg reports.

The U.K. Department of Digital, Culture, Media, and Sport in a statement Monday called for a report detailing implications of the deal by the end of July.

Nvidia announced plans to acquire Arm Holdings after months of rumors back in September. Under the deal, Arm would continue to operate out of its headquarters in Cambridge, England, and will retain its brand, open licensing, and customer neutrality.

At the time, Nvidia also detailed plans to begin construction of an Arm-based supercomputer on Arm’s campus, and license many of its own semiconductor technologies via Arm’s well-established licensing model.

The investigation marks Nvidia’s second snap as it moves forward with the acquisition. In January, the British government began preparing an antitrust investigation into whether the merger could impact competition in the market.

However, unlike this latest investigation, the antitrust investigation did not take into consideration national security concerns.

“We do not believe that this transaction poses any material national security issues,” a spokesperson for Nvidia said in a statement to Bloomberg. “We will continue to work closely with the British authorities as we have done since the announcement of this deal.”

Despite Nvidia’s confidence that the deal will receive necessary regulatory approval, the massive acquisition was expected to face stiff scrutiny in multiple markets, including the United States, United Kingdom, China, and the European Union. This week’s investigation marks the U.K. government’s latest effort to safeguard its most valuable tech company.

U.S.-based Nvidia is also likely to face intense regulatory scrutiny from China, which has been subject to intense trade restrictions that have threatened Chinese semiconductor interests.

In a press conference last week, Nvidia CEO Jensen Huang said the regulatory review process was moving along as expected with completion anticipated for early 2022.