China’s Foreign Ministry spokesperson announced sanctions Monday on US companies Lockheed Martin, Boeing Defense, Space & Security (BDS), Raytheon and others that have sold arms to Taiwan.

The spokesperson said that arms sales to Taiwan “severely violate the one-China principle … and seriously undermine China’s sovereignty and security interests.” The spokesperson urged the US to stop selling arms to Taiwan.

The US State Department announced the $1.8 billion sale last Wednesday. Taiwan’s Defense Ministry stated, “This arms sale shows that the United States attaches great importance to the strategic position of the Indo-Pacific region and the Taiwan Strait, and is actively assisting our country in strengthening our overall defense capabilities.”

The US has no official diplomatic ties with Taiwan, but the Trump administration’s support through arms sales and visits by senior officials serve to add tension between the US and China. China officially considers Taiwan to be a province that it has vowed to bring under its control, using force if necessary.

Exact details of the sanctions have not been announced. US State Department spokesperson Morgan Ortagus said, “We deplore Beijing’s efforts to retaliate against US and foreign companies for their sales that support Taiwan’s legitimate self-defense requirements, the necessity of which has been made abundantly clear through increasingly hostile incursions by [China’s air force].”

Boeing and Lockheed Martin made statements signaling that these sales are strictly regulated by the US government and that the US government is who decides what gets sold to Taiwan.