China threatened on Saturday to take “resolute countermeasures” against a $2 billion sale of arms by the United States to Taiwan.

The deal includes Taiwan’s first purchase of the National Advanced Surface-to-Air Missile System (NASAMS), the cutting-edge U.S. medium-range air defense package.

NASAMS became a hot ticket after the U.S. sent it to Ukraine in November 2022, along with the fabled Patriot anti-missile system. Both proved so effective that the U.S. began routing shipments of the systems from other allies in January 2024 so Ukraine could get more missiles, launchers, and radar systems as quickly as possible.

Norway, which co-developed NASAMS with the United States, also donated millions of dollars in system equipment to the Ukrainians in December. The U.S. and Norwegian companies that developed the system, Raytheon and Kongsberg, used an innovative procurement and delivery strategy to get the system on the ground in Ukraine in about 71 days, much faster than the two to four years that would normally have been required.

The Ukrainians discovered Patriot missiles excel at shooting down Russia’s vaunted “hypersonic missiles,” which Russian President Vladimir Putin once touted as unstoppable super-weapons.

NASAMS proved astonishingly successful at taking out short- and medium-range Russian missiles. In fact, the first two fire units deployed in Ukraine achieved a 100-percent interception rate. The Russians were unable to destroy a NASAMS launch site until February 2024.

China is not happy at the prospect of Taiwan acquiring what could be the most effective air-defense system in the world. Russia’s once-admired air defense systems proved shockingly ineffective against Israel’s strike on Iran over the weekend.

The U.S. approved a $2 billion arms deal including NASAMS on Saturday, drawing immediate condemnation from Beijing. Taiwan said its new air defense systems would help with “maintaining regional stability,” while China claimed the arms deal “endangers peace and security” in the region.

“China strongly condemns and firmly opposes this and has lodged serious protests with the U.S.,” the Chinese Foreign Ministry said.

“We will take resolute countermeasures and take all measures necessary to firmly defend national sovereignty, security and territorial integrity,” the Foreign Ministry added.

“In the face of China’s threats, Taiwan is duty-bound to protect its homeland, and will continue to demonstrate its determination to defend itself,” the Taiwanese Foreign Ministry responded.

China’s state-run Global Times hyperventilated on Sunday that the arms deal was part of an American plot to “economically extort Taiwan region through selling weapons, while benefiting American arms dealers which can profit from escalating tensions.”

Even as it sought to reassure itself that NASAMS will only play a “limited role in enhancing Taiwan’s air defense capabilities” and would pose no threat at all to the People’s Liberation Army (PLA) of China, the Global Times excoriated the U.S. for supporting “Taiwan independence,” a phrase Chinese propagandists always put in scare quotes because the Chinese Communist Party treats the idea like an absurd fantasy.

NASAMS is expected to largely replace Taiwan’s aging Hawk surface-to-air missile system, which is also on its way to Ukraine, thanks to a U.S. policy of buying retired Hawk equipment from Taiwan and shipping it to the Ukrainians. Taiwan formally retired the Hawk system in June 2023, initially replacing Hawk launchers with domestically-developed Tien Kung or “Sky Bow” Mark III surface-to-air missiles.