Yuan Bin and his wife Xu Mei were arrested yesterday several hours after Yuan veered off a commercial flight from Beijing to Kunming in southern China and landed in Taipei.

If convicted of hijacking under civil aviation law the couple could be sentenced to death.

The director of prosecutions in Taoyuan county, south of Taipei, Shih Mao-Lin, said threats were involved when Yuan diverted his plane to Taiwan and the hijack charge was applied for their arrests.

But chief prosecutor Liu Ten-Chen said it remained to be determined if Yuan was hijacking the plane or violating the less severe criminal law of ``endangering the lives of other people'' which carried a maximum five-year prison sentence.

On another possible charge of breaching national security they face a maximum three-year jail term.

It wasnot immediately clear today when the pair would be indicted and under what charges, but a preliminary investigation showed there was no violence in the hijacking.