Director of National Intelligence Dennis C. Blair told a Senate hearing Tuesday that China's military is increasing harassment of U.S. Navy survey ships, activities viewed by U.S. intelligence as the most aggressive since 2001, when a Chinese jet flew into a U.S. EP-3 surveillance plane and set off an international crisis.
Adm. Blair, a former four-star commander of U.S. forces in the Pacific, said a naval standoff Monday near Hainan Island is a troubling sign that China has adopted a more aggressive military posture toward U.S. Navy surveillance ships and is the latest in a series of incidents in international waters.
"In the past several years, they have become more aggressive in asserting that the claims for the [200-mile Economic Exclusion Zone], which are excessive under almost any international code," Adm. Blair told the Senate Armed Services Committee.
"And this latest incident with fishing vessels and a PLA navy vessel involved is the most serious that we've seen since 2001, the EP-3 incident," he said during a hearing on global threats.
A group of Chinese vessels followed and harassed the survey ship USNS Impeccable in the South China Sea on Monday, the Pentagon said.
U.S. diplomatic protests were delivered to the Chinese Foreign Ministry in Beijing and to the Chinese Embassy in Washington.
The incident is expected to be discussed Wednesday when Secretary of State Hillary Rodham Clinton meets Chinese Foreign Minister Yang Jiechi at the State Department, a department spokesman said.
The oceanographic ship was 70 miles south of Hainan Island carrying out routine ocean survey operations in international waters when the Chinese ship and other government vessels approached it, d Pentagon spokesman Bryan Whitman said.
"We view these as unprofessional maneuvers by the Chinese vessels and violations under international law to operate with due regard for the rights and safety of other lawful users of the ocean," Mr. Whitman said.
Chinese Embassy spokesman Wang Baodong said China's Foreign Ministry has addressed the Pentagon claims. In Beijing, the Foreign Ministry rejected the Pentagon protests and said the survey ship "broke international and Chinese laws in the South China Sea without China's permission."
Hainan Island, near where the Impeccable was confronted, is a major Chinese naval and air force base and the expected home port for some of China's new Jin-class nuclear missile submarines.
Mr. Whitman said two of the Chinese vessels sailed within 50 feet of the Impeccable. The ships included a Chinese intelligence collection ship, a Bureau of Maritime Fisheries patrol vessel, a State Oceanographic Administration patrol vessel and two small Chinese-flagged trawlers.
Crew aboard the Chinese ships dropped pieces of wood in the water in front of the Impeccable and two ships moved directly in front of the survey ship, forcing it to stop.
The Chinese also tried to snag the ship's towed acoustic sonar devices.
"These are dangerous close maneuvers that these vessels engaged in," Mr. Whitman said.
Monday's encounter was not an isolated incident. On March 4, a Chinese patrol boat shined a high-powered spotlight on the USNS Victorious that was sailing in international waters in the Yellow Sea, some 125 miles from Chinas coast, the Pentagon said.
Chinese navy maritime aircraft also flew over the ship 12 times on March 5.
Also on March 5, a Chinese warship sailed within 100 yards of the Impeccable after the aircraft buzzed the ship.
On March 7, another Chinese ship warned the Impeccable in a radio communication that its operations were illegal and that it must leave the area or "suffer the consequences," according to a defense official.
China's state-run Inner Mongolia Daily News reported last month that the USNS Bowditch was also shadowed for days by Chinese Y-8 and Y-12 patrol aircraft and navy warships. The report concluded by stating that "if an American spy ship enters China's sea area again, China will sink it."
U.S. survey ships conduct underwater monitoring and are viewed by the Chinese as military intelligence gathering vessels.
The Pentagon has tried for more than a decade to negotiate a maritime agreement with China to prevent such incidents at sea. China's military so far has rejected such an accord.
Foreign Ministry spokesman Ma Zhaoxu said "the U.S. claims are gravely in contravention of the facts and confuse black and white, and they are totally unacceptable to China."
"We demand that the United States put an immediate stop to related activities and take effective measures to prevent similar acts from happening," Mr. Ma told reporters.
The spokesman did not provide details of what happened or explain how the U.S. ship violated laws.
"We expect Chinese ships to act responsibly and refrain from provocative activities that could lead to miscalculation or a collision at sea, endangering vessels and the lives of U.S. and Chinese mariners," a Pentagon official said.
Richard Fisher, a military analyst with the International Assessment and Strategy Center, said the harassment of U.S. survey ships by China comes as Beijing is using its own survey ships to assert control over Japanese waters considered part of Tokyo's economic zone.
Additionally, the Chinese navy is seeking to build aircraft carriers and the missile submarine base on Hainnan, he said.
The activities appear to be "the beginnings of a battle led by the PLA to assert control over the Western Pacific sea lanes," Mr. Fisher said.
Mr. Fisher said he hopes the Obama administration will not give up the survey ship missions which he said are critical to American security and alliance interests in the Pacific.
"These surveys ship missions are all about monitoring sea conditions, data that is increasingly critical to successful anti-submarine operations, especially as submarines grow increasingly more difficult to detect by sonar alone," he said.