BEIJING:China suspended military exchange visits with the United States on Saturday in protest over $6.4 billion in planned U.S. arms sales to Taiwan and warned the U.S. ambassador that the sales would harm already strained ties.

The state-run Xinhua News Agency cited the Defense Ministry as saying the suspension is due to the "severe harm" of the arms sales on the two countries' military relations.

China took a similar step in 2008 after the former Bush administration announced a multibillion-dollar arms sale to Taiwan — the most sensitive issue in U.S.-China relations. The latest arms sales could complicate the cooperation the U.S. seeks on issues ranging from Iran's nuclear program to the loosening of Internet controls, including a Google-China standoff over censorship.

China claims the self-governing Taiwan as its own, while the United States is Taiwan's most important ally and largest arms supplier. The U.S. government is bound by law to ensure the island is able to respond to Chinese threats.

Though Taiwan's ties with China have warmed considerably since Taiwanese President Ma Ying-jeou took office 20 months ago, Beijing has threatened to invade if the island ever formalizes its de facto independence. China has more than 1,000 ballistic missiles aimed at Taiwan.

The arms sale, posted Friday on a Pentagon Web site, includes Black Hawk helicopters, Patriot Advanced Capability-3 missiles, mine hunter ships and information technology. Congress has 30 days to comment before the plan goes forward. Lawmakers traditionally have supported such sales.

Upcoming high-level visits are likely to be affected by the China's suspension of military exchanges. Gen. Chen Bingde, the Chinese military's chief of the general staff, was due to visit the U.S., while U.S. Secretary of Defense Robert Gates and Admiral Michael Mullen, Chairman of the U.S. Joint Chiefs of Staff, had planned to come to China.

A phone call to China's defense ministry seeking comment was not answered Saturday. A spokeswoman for the U.S. Embassy, Susan Stevenson, said the embassy had no comment on the suspension of military visits.

The two powers are increasingly linked in security and economic issues, and Washington has sought to raise the profile and frequency of military visits with China and build trust with Beijing to convince it to reveal more about the aims of its massive military buildup.

But overall ties have been tense as President Barack Obama plans to meet with the Dalai Lama, the exiled spiritual leader of Tibet, later this year. Further complications from the Taiwan arms sale could affect President Hu Jintao's expected visit to the U.S. this year, as well as talks on human rights that Obama and Hu had agreed to continue.

Obama's national security adviser, Jim Jones, said in a speech Friday that both Washington and Beijing do things "periodically that may not make everybody completely happy" but that the United States is "bent toward a new relationship with China as a rising power in the world."

But experts in China warned it could take further steps to punish the United States to underscore its newfound power and confidence in world affairs.

Also Saturday, Vice Foreign Minister He Yafei warned U.S. Ambassador Jon Huntsman that the $6.4 billion sale would "cause consequences that both sides are unwilling to see." The vice minister urged that the sale be immediately canceled, it said.

The U.S. is "obstinately making the wrong decision," China's Foreign Ministry said in a statement.

Jin Canrong, a professor of international studies at China's Renmin University, said the sale would give Beijing a "fair and proper reason" to accelerate weapons testing.

Beijing has test-fired rockets in recent weeks for an anti-missile defense system in what security experts said was a display of anger at the pending arms sale.

"The U.S. will pay a price for this. Starting now, China will make some substantial retaliation, such as reducing cooperation on the North Korea and Iran nuclear issues and anti-terrorism work," Jin added.

The arms package, however, dodges a thorny issue: more advanced F-16 fighter jets that Taiwan covets are not included.

The Pentagon's decision not to include the fighters and a design plan for diesel submarines — two items Taiwan wants most — "shows that the Obama administration is deeply concerned about China's response," said Wang Kao-cheng, a defense expert at Taipei's Tamkang University.

Taiwan's president Ma told reporters Saturday that the deal should not anger the mainland because the weapons are defensive, not offensive.

"The weapons sale decision will ... allow us to have more confidence and sense of security in developing cross-Strait relations," he said.