TAIPEI: The United States confirmed the sale to Taiwan of an advanced air defence missile system worth almost US$700 million, which has been battle-tested in Ukraine, in the second such weapons package for Taipei in a week.In the Indo-Pacific region, only Australia and Indonesia now operate the system, three of which the United States said last year Taiwan would receive as part of a US$2-billion weapons sale.The National Advanced Surface-to-Air Missile System (NASAMS) medium-range air defence solutions, as they are called, are made by RTX and are a new weapon for Taiwan.The Pentagon said the company was given a firm fixed-price contract for procurement of the NASAMS units, with work estimated to be completed in February 2031."Fiscal 2026 foreign military sales (Taiwan) funds in the amount of US$698,948,760 were obligated," it said in a statement on Monday (Nov 17).RTX did not immediately respond to a request for comment.Used in Ukraine to defend against the Russian invasion, the NASAMS system offers a sharp boost in air defence capabilities that the United States is exporting to Taiwan as demand for it surges.The US approved the sale of fighter jet and other aircraft parts to Taiwan for US$330 million on Thursday, in the first such deal since President Donald Trump took office in January, prompting thanks from Taipei and anger in Beijing.The arms sales news comes amid a worsening diplomatic crisis between Beijing and Tokyo over Taiwan, claimed by China as its own territory, although the island's government rejects Beijing's sovereignty claims.On Sunday, Chinese coast guard ships sailed through waters around a group of East China Sea islands controlled by Japan but claimed by China.