Activists opposing Japan's control of the Diaoyu Islands yesterday accused their Government of treachery after Premier Lien Chan blocked their plans to fly two rented helicopters to the islands today. The protesters, led by a group of retired air force pilots calling themselves the New Air Force, had planned to land at least one helicopter on the Diaoyus today, the 51st anniversary of Taiwan's liberation from Japanese rule. The decision to reject the protesters' flight plan was authorised by Mr Lien after a special Diaoyus policy task force recommended late on Wednesday that blocking the flights would be in the national interest. Earlier yesterday, Vice-Foreign Minister Tzen Wen-hua , who presided over Wednesday's meeting, said the decision was handed down with the national interest in mind. 'The controversy over the Diaoyus' sovereignty won't be resolved in the short term,' he said. 'Any overzealous actions not only won't help resolve the problem, they would also not conform to the overall national interest.' The protest group filed a petition with the Control Yuan, Taiwan's highest government agency charged with monitoring the civil service for incompetence and impropriety. 'We want to file a petition against these people for sacrificing the country's rights and insulting the nation,' said Tsao Shen-pao , leader of the New Air Force. Feng Fu-hsiang , secretary-general of the Alliance for the Defence of the Diaoyus, said it had been decided to temporarily postpone the plan, but they would not give up until they had achieved their goal.