BEIJING — China warned the United States Wednesday its arms sales to Taiwan will cause "devastating damage" to Sino-U.S. relations, with cooperation on nonproliferation the first casualty.

U.S. Ambassador Joseph Prueher was summoned to hear the strongest protest yet by Beijing to an arms package for Taiwan unveiled Tuesday that included offers to supply sophisticated destroyers, aircraft and submarines.

"The Chinese government and people express strong indignation and absolute opposition to this decision," state television quoted Vice-Foreign Minister Li Zhaoxing as telling Prueher.

The decision "will have a grave impact on China-U.S. cooperation in the sphere of non-proliferation and bring devastating damage to China-U.S. relations," Li said. He also threatened further consequences, saying "China reserves the right to make a further reaction."

President Bush, meanwhile, toughened the U.S. position on Taiwan by abandoning a long-standing ambiguity and declaring the United States would defend the island if it was attacked by China.

There was no immediate Chinese reaction to that.

But Bush also tossed a few olive branches to Beijing, telling the Washington Post he did not view China as an "enemy" and announcing an end to annual reviews of arms sales to Taiwan.

Chinese Foreign Minister Tang Jiaxuan said the arms sales "interfered with the sovereignty of China and its internal affairs."

Beijing regards Taiwan as a wayward province to be reunified by force if necessary.

"I am deeply convinced that the Americans themselves will suffer from this," Tang said during a visit to Ukraine.

In an interview taped for ABC's "Good Morning America" on Wednesday, Bush said Washington would do "whatever it took" to defend Taiwan.

Asked whether Washington had an obligation to defend Taiwan from Chinese attack, Bush said: "Yes, we do and the Chinese must understand that."

Previous U.S. administrations have stopped just short of promising to send forces to Taiwan's aid in the event of war with China, although they they have sent strong signals that they would intervene.

Under the 1979 Taiwan Relations Act, the U.S. administration is obliged to provide Taiwan with enough arms to defend itself.

But Bush told the Washington Post a near 20-year policy of annual reviews for providing such arms would be scrapped.

Such reviews put U.S. administrations in an awkward position by having to publicly approve or reject items in a long shopping list of arms presented by Taiwan, which has powerful support in Congress. "We have made it clear to the Taiwanese that we will not have this so-called annual review — that we will meet on an as-needed basis," Bush told the newspaper.

Bush said he expected his state visit to China would go ahead as planned in October.

"And I do not view China as an enemy," he added.

"I view China as a partner on some issues and a competitor on others," he said. Competition "does not necessarily mean distrust, anger, you know, furor."

China has an estimated 300 missiles pointed at Taiwan along its southeastern coast and the United States estimates it is adding about 50 every year.

Beijing has spent billions of dollars on sophisticated Russian weaponry and has so far bought about 50 SU-27 fighter jets, four Kilo class diesel submarines and two Sovremenny destroyers armed with "Sunburn" anti-ship cruise missiles.

In Taiwan, a statement issued by the presidential office said the latest arms package would help redress the balance.

"This helps to raise Taiwan's defenses, fortify the people's confidence and also maintain a military balance and stability in the Taiwan Strait," the statement said.

"It will be conducive to opening constructive dialogue between the two sides on an equal basis."