The White House late Monday issued an order blocking Broadcom's proposed takeover of fellow chip maker Qualcomm on national security grounds.

President Trump wrote that he reviewed the recommendations of the Committee on Foreign Investment in the U.S. and that he possesses authority under the Defense Production Act of 1950 to "protect the national security" by prohibiting the acquisition.

The order also bans Broadcom-backed candidates for Qualcomm's board of directors from standing for election at an upcoming shareholders' meeting and directs Qualcomm to provide notice of the meeting "as soon as possible." Qualcomm officials said the meeting would take place on March 23.

"Any transaction or other device entered into or employed for the purpose of, or with the effect of, avoiding or circumventing this order is prohibited," Trump wrote in the order.

Broadcom last year made an unsolicited bid for Qualcomm in what would have been the largest tech industry merger in history. Qualcomm executives resisted the campaign as Broadcom offered its own slate of board candidates and raised the price of its offer, but reports suggested that Broadcom's candidates were gaining support among Qualcomm investors.

The shareholders' meeting was originally scheduled for last week, but CFIUS, in an unprecedented move, postponed the event so it could pre-emptively review the national security implications of the merger.

A combined company would make the chips and semiconductors in many of the world's mobile devices, and the Trump administration — which was already concerned about the standing of the U.S. in the race to 5G — worried about the impact of a deal on Qualcomm's research and development efforts.

Some lawmakers also criticized the takeover of a key domestic tech company by an overseas competitor, although Broadcom is in the process of officially relocating from Singapore to Delaware.

Broadcom, which vowed to maintain Qualcomm's 5G R&D, said in a statement that it is reviewing the White House order.

"Broadcom strongly disagrees that its proposed acquisition of Qualcomm raises any national security concerns," the company said.