The State Department signaled its approval for a potential $2.4 billion sale of anti-ship missiles to Taiwan.
The Trump administration said in a statement Monday that it has notified Congress that it backs the proposed sale of as many as 100 Harpoon Coastal Defense Systems built by Boeing Co., which include 400 land-based missiles.
The new Harpoon anti-ship missiles are intended to be launched from ground-mobile launchers, adding to Taiwan's arsenal of air and submarine-launched Harpoons from earlier sales.
"The United States maintains an abiding interest in peace and stability in the Taiwan Strait and considers the security of Taiwan central to the security and stability of the broader Indo-Pacific region," the State Department said in a statement.
China said earlier that it would impose unspecified sanctions on Boeing's defense unit, Lockheed Martin Corp. and Raytheon Technologies Corp. after the U.S. approved $1.8 billion in arms sales to Taiwan last week and made a previous announcement of 66 new F-16 jets.
Taiwan thanked the U.S. for the latest arms sale in a statement posted on the presidential office website.
China said Tuesday that it would take "necessary measures" to uphold its sovereignty and security interests.
"We urge the U.S. side to stop arms sales and military contact with Taiwan and withdraw the arms sales plan to avoid harming China-U.S. relations as well as cross-strait peace and stability," Chinese Foreign Ministry spokesman Wang Wenbin told reporters at a daily briefing in Beijing.
In August, the U.S. and Taiwan completed the sale of 66 new model F-16 Block 70 aircraft from Lockheed. Zhao Lijian, another Chinese foreign ministry spokesman, condemned it at the time, saying it crossed Beijing's bottom line that both sides belong to "One China" and would have a "major impact" on U.S.-China relations.
In July, China -- which considers Taiwan part of its territory and resists any recognition of its de facto independence -- had announced sanctions on Lockheed Martin for a previous arms sale to the island.
Lockheed hasn't seen any "material impact" on its sales from earlier sanctions, announced July 14, for selling Patriot Advanced Capability-3, or PAC-3, missile batteries to Taiwan, the company said in a filing last week. The world's largest defense contractor derives less than 1% of its revenue from China, a Lockheed spokesman said.
China's moves this year to exercise greater control over Hong Kong prompted many analysts to see the risks rising for Taiwan.
Two senior Trump administration officials have traveled to Taiwan in recent months, underscoring U.S. support for the island and prompting China to bolster its military posture.
Ahead of Undersecretary of State Keith Krach's visit to Taipei last month, for instance, two Chinese anti-submarine aircraft entered the air-defense-identification zone around the island, the Taiwanese Ministry of National Defense said in a statement. The incursion came after China's military sparked concern by sending more than 20 aircraft into the zone for two days in a row.
Also last month, the People's Liberation Army Air Force released a video showing H-6 bombers making a simulated strike on a runway that looked similar to one at Anderson Air Force Base on Guam, a key staging area for any U.S. support for Taiwan.