Qualcomm Inc. (QCOM) - Get Report shares slumped in pre-market trading Tuesday after U.S. President Donald Trump blocked Singapore chipmaker Broadcom Inc.'s (AVGO) - Get Report  attempt to buy the San Diego, Calif.-baed group  citing national security concerns that will scupper the tech sector's biggest ever takeover

Trump said he had "credible evidence" that Broadcom's $117 billion play for the group, which had been under review by the Committee on Foreign Investment in the United States (CFIUS), may result in actions that "impair the national security of the United States", and order both companies to "immediately and permanently abandon the proposed takeover" in an Executive Order signed late Monday. 

"The proposed takeover of Qualcomm by the Purchaser is prohibited, and any substantially equivalent merger, acquisition, or takeover, whether effected directly or indirectly, is also prohibited," a statement from the White House read. "All 15 individuals listed as potential candidates on the Form of Blue Proxy Card filed by Broadcom and Broadcom Corporation with the Securities and Exchange Commission on February 20, 2018, are hereby disqualified from standing for election as directors of Qualcomm."

Qualcomm shares were marked 5.75% lower from their Monday close during pre-market trading, indicating an opening bell price of $59.20, the lowest since Nov. 2, just days before Broadcom's $70 a share bid was initially revealed on Nov. 6. Broadcom shares were marked 1.39% higher and were indicated to open at $266.50 each. 

Intel Corp. (INTC) - Get Report , which has been linked to a potential play for Broadcom, was also active in pre-market, rising 2.19% to a year-to-date high of $52.65 each. TheStreet's Brian Sozzi discusses potential Intel interest in Broadcom below. 

"Broadcom is reviewing the Order," the company said in a statement. "Broadcom strongly disagrees that its proposed acquisition of Qualcomm raises any national security concerns." Qualcomm said in a statement it would reconvene its annual shareholder meeting for March 23.

Qualcomm, which makes wireless communications systems, including 5G networks, was seen as a prized asset for both domestic and foreign buyers as it emerged as key rival to China's Huawei Technologies.

China has targeted the buildup of its domestic optical components industry, which makes equipment for wireless networks, as part of its recent "five-year plan" for the world's second largest economy. 

Trump's decision to thwart a takeover of Qualcomm, whose industry expertise is crucial to the U.S. maintaining its lead over China-based rivals in wireless network development, is likely to be seen as a legitimate attempt to protect American interests -- both business and military -- from potential hacking or data integrity attacks aboard.

"A shift to Chinese dominance in 5G would have substantial negative national security consequences for the United States," CFIUS said on March 5. "While the United States remains dominant in the standards-setting space currently, China would likely compete robustly to fill any void left by Qualcomm as a result of this hostile takeover."

The decision could also cast a pall over tech sector takeovers and could face legal challenges, TheStreet's Ron Orol and Brian Sozzi wrote yesterday, noting that "U.S. companies will need to consider whether they do business with China or whether the technology or service they offer is considered vital for national security."