China said Monday it would sanction American military contractors including Lockheed Martin, Raytheon Technologies and Boeing's defense division for selling weapons to Taiwan.

The U.S. approved $1.8 billion in weapons sales to Taiwan last week.

The sanctions will be implemented "in order to protect national interests," Zhao Lijian, China's Foreign Ministry representative, said Monday. Zhao didn't provide details of penalties.

China's ruling Communist Party claims Taiwan as part of its sovereignty and has threatened to invade. The U.S. promised to cut and eventually terminate the sale of arms to Taiwan in the 1980s but asserts its discord with China must be settled amicably. Taiwan split with China in 1949.

According to Zhao, to safeguard China's national interests, it decided to "take necessary measures and levy sanctions" on the U.S. companies, including individuals and companies "who behaved badly in the process of the arms sales," he said.

The U.S. has no official diplomatic relations with Taiwan but said it was bound by law to provide Taiwan with the capability to defend itself from intrusion.

A Boeing representative emphasized the group's ties with China in the aerospace business. Boeing has "worked successfully with the aviation community in China for almost 50 years to support the country's efforts to ensure a safe, efficient and profitable aviation system to keep pace with China's fast economic growth," Bloomberg quoted the representative as saying.

Last week, China demanded the U.S. suspend a planned sale of 135 land attack missiles sold for $1 billion to boost Taiwan's defenses. Zhao said the sale "seriously undermines" China's sovereignty and security interests.