The United States last night formally offered Taiwan a sweeping package of arms to counter China's military expansion, including destroyers and submarines. The deal approved by the administration of President George W. Bush - estimated at more than US$4 billion (HK$31.2 billion) - represents the biggest annual offer of weapons to Taiwan since the sale of 150 F-16 fighters in 1992. However, a request for ships with sophisticated naval radar, along with other hi-tech arms, was not approved. The expected deal with Taipei threatens Sino-US relations, still reeling from this month's spy plane stand-off on Hainan Island. The Foreign Ministry in Beijing expressed serious concern at the news, warning of fresh tensions across the Taiwan Strait. Acting on recommendations from Defence Secretary Donald Rumsfeld, Mr Bush approved the sale of four Kidd-class destroyers, eight diesel-powered submarines and 12 P-3 sub-hunting aircraft. Significantly, however, the Bush team further deferred a decision on the sale of ships carrying the powerful Aegis battle management radar - a crack system Beijing has made privately clear would be unacceptable. The Aegis - capable of tracking 100 planes, ships or missiles simultaneously - was the key item on the Taiwan wish-list. It would have been ready by 2009 at the earliest. Also denied were army requests for M-1 tanks and Apache helicopters, with the Bush team clearly wanting to boost the island's troubled navy. White House officials said they wanted to act firmly to help Taiwan defend itself under the terms of the Taiwan Relations Act but stressed they did not want to scupper relations with Beijing. 'We think there is nothing in this package for China to fear,' one White House official said. The deal was unveiled to a visiting Taiwanese military delegation last night and has yet to be announced officially. Foreign Ministry spokeswoman Zhang Qiyue said in Beijing: 'We are strongly opposed to the arms sales. We urge the United States to exercise prudence.' China declared the decision was a violation of previous bilateral agreements that the US would not sell arms above the level of those existing when the two countries opened diplomatic relations in 1979. 'If the US disregards China's solemn representation, it would be a grave violation of China's sovereignty, rude interference in China's internal affairs and would increase tension across the Taiwan Strait,' Ms Zhang said. She dismissed as groundless and an excuse reports that China was rapidly expanding missile bases in Fujian province to threaten Taiwan. Beijing's envoy to the US, Yang Jiechi, later delivered a formal protest letter to the State Department. The submarines - geared to protecting Taiwan from Beijing's expanding 40-vessel fleet - could be particularly contentious with China viewing them as offensive weapons. Previous US administrations had skirted their sale. The four Kidd-class destroyers are considered a generation behind current US technology but are seen as a vital middle step to more impressive ships later on. Currently sitting in ports near Seattle and Philadelphia as part of the US Strategic Reserve, the Kidds will require a full refit but could be ready in 18 months. Last night, Xinhua released an article to be published in the Liberation Army Daily today denouncing Taiwan's plan to buy the weapons from the US. It ridiculed Taiwan President Chen Shui-bian for seeking US protection and said Beijing did not consider the weapons the US would sell as 'defensive'. Wu Xinbo, a professor at the Fudan University Centre for American Studies in Shanghai, told Reuters that China's response would go beyond words because of the submarines, which could also target Chinese cities. 'At this stage protest is too mild an action, given this break of the red line,' he said. 'I think there will be some substantive actions and this will come very soon.' He declined to speculate on what actions Beijing might take but said the Government would 'make the US acutely aware of the cost of its behaviour on this issue and remind the US about the relative gain or loss from its Taiwan policy'.