The United States is not required to defend Taiwan if Beijing launches a war against the island, according to a leading US official. The remarks by Deputy Secretary of State Richard Armitage, in an interview aired on US television on Monday, are seen as Washington's latest attempt to stop the island tilting further towards independence. Mr Armitage described Taiwan as the biggest landmine in Sino-US relations. Asked whether the US would defend Taiwan in the event of an attack, Mr Armitage said: 'We have the requirement with the Taiwan Relations Act to keep sufficient force in the Pacific to be able to deter attack; we are not required to defend. And these are questions that actually reside with the US Congress, which has to declare an act of war.' Mr Armitage stressed that there was only one China and that Taiwan was part of it. Joseph Wu Jau-shieh, chairman of Taiwan's Mainland Affairs Council, last night downplayed Mr Armitage's remarks, saying he did not think they signalled a reversal of Washington's policy. Dr Wu admitted the US had no obligation to send troops to Taiwan under the Taiwan Relations Act. 'But it does have the obligation to supply defensive arms to Taiwan.' The opposition Kuomintang's Chang Yung-kung, who was formerly the party's China affairs director, said the remarks were a warning that the ruling Democratic Progressive Party should abandon its independence moves.