The deal includes anti-missile defences and helicopters
The Pentagon has notified Congress of a proposed arms sale to Taiwan, worth $6bn (£3.7bn).
The weapons, including helicopters and anti-missile defences, are part of a package first pledged by the Bush administration.
Beijing considers the self-governed island a breakaway province of China and reacted angrily, saying the move would "seriously damage" its US ties.
Taiwan split from China at the end of the country's civil war in 1949.
Beijing has hundreds of missiles pointed at the island and has threatened in the past to use force to bring it under its control.
The $6.7bn (£4.2bn) package does not include F-16 fighter jets, an item highly desired by Taiwan's military.
PROPOSED ARMS SALE
114 Patriot missiles ($2.81bn)
60 Black Hawk helicopters ($3.1bn)
Communication equipment ($340m)
2 Osprey mine-hunting ships ($105m)
12 Harpoon missiles ($37m)
Source: Defense Security Co-operation Agency
The notification to Congress by the Defense Security Co-operation Agency is required by law and does not mean the sale has been concluded.
US lawmakers have 30 days to comment on the proposed sale, Associated Press reported. If there are no objections, it would proceed.
The arms package includes 114 Patriot missiles, 60 Black Hawk helicopters and communications equipment for Taiwan's F-16 fleet, the agency said in a statement.
Chinese Vice Foreign Minister He Yafei said the proposals would have a "serious negative impact" on co-operation between the US and China.
In remarks published on the website of the Chinese Foreign Ministry, he said the Chinese government was "strongly indignant" about the arms sales.
Beijing has previously warned the US not to go ahead with arms sales to Taiwan. Ties between China and the US are already strained by rows over trade and internet censorship.
The DSCA said the proposed sale would support Taiwan's "continuing efforts to modernise its armed forces and enhance its defensive capability."
It added: "The proposed sale will help improve the security of the recipient and assist in maintaining political stability, military balance, and economic progress in the region."
The US is the leading arms supplier to Taiwan, despite switching diplomatic recognition from Taipei to Beijing in 1979.