Taiwan President Tsai Ing-wen on Friday rejected a Chinese threat to impose sanctions on U.S. firms involved in sales of weapons to Taiwan.

The U.S. State Department recently approved a planned sale of tanks and missiles to Taiwan for an estimated cost of $2.22 billion, triggering a strong protest by China and potentially giving a fresh twist to the prolonged trade battle between the world's two largest economies.

"I think it is very legitimate that we look for any opportunity to strengthen our defense capability and we appreciate the U.S. government's assistance in this so far," Tsai told reporters in New York, where she arrived the previous day en route to diplomatic allies in the Caribbean.