The US official emphasized that there is "no change to our longstanding 'One China' policy" -- stating that there is only one China and that Taiwan is part of it -- which Beijing says is a prerequisite for maintaining relations.
Announcement of the sale comes at a sensitive moment for the US and China, as President Trump is working to establish a partnership over trade differences and efforts to curb North Korea's nuclear program.
The Trump administration has formally notified Congress of the defense sales comprised of seven parts, the official said, which are "based on an assessment of Taiwan's defense needs" and include upgrading defense systems from analog to digital.
The plans are consistent with terms of the 1979 Taiwan Relations Act, the official said, under which Washington keeps trade ties and sells Taipei weapons to "maintain a sufficient self-defense capability."
US legislation designed to provide democratic Taiwan with enough military clout to defend itself against China's vastly superior armed forces, requires Washington to sell high-end weaponry to Taipei.
The last US arms sale to Taiwan was in December 2015.
Just after winning election, Trump infuriated Beijing by accepting a congratulatory call from Taiwan's President Tsai Ing-wen, but once in office the president unequivocally endorsed the "One China" policy during a visit by Chinese leader Xi Jinping.
While Washington cut off formal diplomatic ties with Taipei, it has never made a clear statement about Taiwan's sovereignty, and the island enjoys many of the trappings of diplomatic relations with the US.
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