The jet disappeared around half an hour after taking off for a routine training flight from a base in the southern city of Chiayi, the air force said in a statement.

Taiwan's national rescue centre reported that people saw the F-16V "crashing into the sea," adding that two choppers and one coastguard vessel had been dispatched to find the jet.

President Tsai Ing-wen has ordered an all-out rescue effort and asked for clarity around the cause of the incident, her office said.

Taipei commissioned its first squadron of US-made F-16V fighters in November in an effort to upgrade its ageing fleet as tensions with China continue to heighten. Beijing claims the self-ruled island as part of its territory and has vowed to take it one day, by force if necessary.

The F-16V is an upgraded and much more sophisticated version of the island's other F-16 fighters which date back to the 1990s.

The air force has suffered a string of fatal accidents in recent years as its jets are kept under growing pressure from China.

Taiwan also has French-made Mirage jets and its own indigenous warplanes.