Beijing has vowed to take "resolute countermeasures" to defend its sovereignty following US approval of US$385 million in arms sales to Taiwan.
The foreign ministry said on Sunday that the US decision was an infringement of China's sovereignty and would harm relations between the two countries.
It urged the United States to immediately stop arming Taiwan and stop condoning support for separatist forces that "seek independence by force".
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"The sales seriously undermine China's sovereignty and security interests, seriously violate international law and send a gravely wrong message to 'Taiwan independence' separatist forces," the ministry said.
"China will take strong measures to resolutely counter and firmly defend national sovereignty, security and territorial integrity."
The Pentagon's Defence Security Cooperation Agency (DSCA) said on Friday that the US State Department had a request from Taiwan for about US$320 million in spare parts and support for F-16 fighter jets and radar equipment.
"The proposed sale will improve the recipient's ability to meet current and future threats by maintaining the operational readiness of the recipient's fleet of F-16 aircraft," the agency said.
The department, which also approved US$65 million in technical support for communications systems, said the proposed sales would not "alter the basic military balance in the region".
Deliveries are expected to begin next year.
Beijing sees Taiwan as part of China to be reunited by force if necessary. The United States, like most countries, does not recognise Taiwan as an independent state, but is opposed to any attempt to take the self-governed island by force and is committed to arming it for defence.
The office of Taiwanese leader William Lai Ching-te said the package was the 18th military sale to Taipei announced since US President Joe Biden took office in 2021.
The announcement of the approval came on the eve of Lai's departure on a trip to the Marshall Islands, Tuvalu and Palau, Taipei's three diplomatic allies in the Pacific.
The trip includes stopovers in the US state of Hawaii and in Guam, a US territory.
Beijing also said on Sunday that it "strongly condemned" the US for arranging the stopovers and had lodged serious protests with Washington.