Beijing has strongly protested a U.S. plan to sell $1.4 billion worth of arms to Taiwan and demanded that the deal be canceled.
Chinese foreign ministry spokesman Lu Kang Friday said Washington should immediately stop the sale to avoid harming relations with Beijing.
He said the deal would severely damage China's sovereignty and security interests and runs contrary to Washington's commitment to a "one-China" policy.
The U.S. State Department approved the arms sales Thursday, the first such deal with Taiwan since President Donald Trump took office. Taiwan has welcomed the agreement, which is expected to enhance the island's self-defense capability.
Beijing regards Taiwan as part of China's territory and prohibits countries with which it has diplomatic relations from pursuing official ties with Taiwan.
A U.S. government official said US arms sales to Taiwan reflect no change in the long-standing One China policy, which recognizes the People's Republic of China.
The sales comply with the Taiwan Relations Act and are based on an assessment of Taiwan's defense needs, he added.
The equipment includes technical support for early warning radar surveillance, missiles and torpedoes. The sales represent upgrades, including equipment needed to convert current defensive systems from analog to digital, the official said.
"There is continuity here - the United States has been doing defense sales with Taiwan for 50 years or so, so nothing has changed," said State Department spokeswoman Heather Nauert.
Taiwan government spokesman Sidney Lin said the sale increases the country's self-defense abilities and "confidence and ability to maintain the status quo of peace and stability across the Taiwan Strait."
Lai I-chung, a senior political analyst of Taiwan Think-tank, said the approval of the arms sale showed that relations between Taiwan and the U.S. remained steady, according to the Central News Agency.
Under the 1979 Taiwan Relations Act, the U.S. assures "Taiwan's ability to maintain a sufficient self-defense capability."
The last U.S. arms sales to Taiwan, worth 1.83 billion US dollars, was authorized by the Obama administration in December 2015.