US companies involved in a potential arms sale worth US$2,2 billion to self-ruled Taiwan will face sanctions, China said, warning Washington “not to play with fire”.

Taiwan on Saturday defended the weapons purchase, saying it will strengthen Taiwan’s self-defence in the face of a growing military threat from China.

“The national army will continue to strengthen its key defence forces, ensure national security, protect its homeland, and ensure that the fruits of freedom and democracy won’t be attacked,” the defence ministry said in a statement.

The planned weapons sale, the first transfer of big-ticket US military gear to democratically governed Taiwan in decades, came as ties between Washington and Beijing are already strained by a trade war.

“The US arms sale to Taiwan has severely violated the basic norms of international law and international relations,” Chinese foreign ministry spokesman Geng Shuang said in a statement on Friday.

“In order to safeguard national interests, China will impose sanctions on US enterprises participating in this sale of weapons to Taiwan,” he said.

Foreign Minister Wang Yi, during a visit to Hungary, asked the US to “recognise the gravity of the Taiwan question”.

China, which views Taiwan as part of its territory, bristles at any country that lends the island state any diplomatic support or legitimacy.

Even though Taiwan, which split from China following a civil war in 1949, doesn’t have diplomatic ties with the US, Washington provides Taipei with military and other support. Beijing regards this as interference in its internal affairs.State media