(Shanghai) Chinese authorities announced sanctions on Sunday against five American defense companies in response to arms sales to Taiwan, which Beijing considers an integral part of its territory.

Last month, the U.S. State Department approved a $300 million weapons program to strengthen Taipei’s joint warfighting command and control system.

Beijing then declared that it would take “countermeasures” against the companies involved without immediately specifying their nature.

China’s Foreign Ministry announced on Sunday that defense companies BAE Systems Land and Armament, Alliant Techsystems Operation, AeroVironment, ViaSat and Data Link Solutions would be targeted by the sanctions.

“The countermeasures include freezing the assets of these companies in China, including their movable and immovable property, and prohibiting organizations and individuals in China from conducting transactions and cooperating with them,” the ministry said. “US arms sales to China’s Taiwan region… seriously harm China’s sovereignty and security interests,” the statement added.

Beijing has increased pressure on Taiwan since pro-independence President Tsai Ing-wen came to power in 2016.

Beijing regularly sends warplanes and ships near the island, and Taiwan’s Defense Ministry recently reported several sightings of balloons sent from mainland China. Washington and Taipei have warned Beijing against any attempt to influence the presidential elections which will be held in Taiwan in mid-January.

China, which considers Taiwan as an integral part of its territory, has vowed to one day bring the island back into its fold, using force if necessary.