"The proposed takeover of Qualcomm by the Purchaser [Broadcom] is prohibited, and any substantially equivalent merger, acquisition, or takeover, whether effected directly or indirectly, is also prohibited," the order said on Monday.
There is credible evidence, the order said, that through exercising control of Qualcomm, Broadcom "might take action that threatens to impair the national security of the United States."
The Trump Adminstration's move reportedly shows the high value of the US on maintaining the domestic edge in the technological development.
Last week, The Washington Post reported that the US Committee on Foreign Investment has sent a letter to the attorneys of the two companies saying it was concerned about the alleged development at Qualcomm might atrophy under Broadcomm's direction. If that happened, China's Huawei, a rival to Qualcomm and a major mobile hardware producer, might reportedly gain dominance on the world's market.