The Biden administration is preparing to sell US$1.1 billion (S$1.5 billion) in missiles and radar support to Taiwan, according to an official familiar with the matter.
The package would include as much as US$650 million in continued support for a surveillance radar sold earlier, about US$90 million for roughly 100 Sidewinder air-to-air missiles as well as about 60 additional anti-ship Harpoon missiles, the official said. Both weapons have been sold to Taiwan previously.
The State Department informally notified Congress of the sale late on Monday (Aug 29).
Even though it offers Taiwan no new military capability, the move will anger China, which has become more aggressive in its military posture against the island. Politico reported on the planned arms sale earlier on Monday.
China regards Taiwan as a renegade province awaiting reunification with the mainland, by force if necessary. Taiwan says it will defend its freedoms and democracy, insisting that only the Taiwanese people can decide the island's future.
The notification marks the beginning of several weeks of staff consultations that will result in a formal arms-sale proposal from the State Department. But support for Taiwan is running high among both Republicans and Democrats, meaning that the package will likely face little resistance from Congress.
A separate person familiar with the matter said there have been several conversations between the administration and Congress about arms sales to Taiwan.
A spokesman for the US National Security Council, speaking on condition of anonymity, declined to respond in detail and said only that the US would continue fulfilling its responsibilities under the Taiwan Relations Act to support Taiwan's self-defence.
A State Department spokesman said that as a matter of policy, the department does not publicly comment or confirm proposed defence sales until they have been formally notified to Congress.
Washington diplomatically recognises Beijing over Taipei, but maintains de facto relations with Taiwan and supports the island's right to decide its own future.
Earlier this month, House Speaker Nancy Pelosi became the highest-ranking US official in a quarter century to visit Taiwan, prompting Beijing to conduct military drills after her visit and fire missiles over the island for the first time.
Chinese warplanes have breached the median line that divides the Taiwan Strait on a near-daily basis since Mrs Pelosi's visit.
Since then, Senator Edward Markey, a Massachusetts Democrat, and Senator Marsha Blackburn, a Tennessee Republican, have also made high-profile trips there.
Taiwan President Tsai Ing-wen has welcomed the visits from the US lawmakers as an "active show of strong support of the US Congress", adding that they had "reinforced Taiwan's determination to defend itself".
Taiwan last week proposed raising its total spending on the military by almost 14 per cent next year.