The Pentagon charged Monday that five Chinese ships shadowed and maneuvered dangerously close to a U.S. Navy vessel in an apparent attempt to harass the American crew.
Defense officials in the Obama administration said the incident Sunday followed several days of "increasingly aggressive" acts by Chinese ships in the region. The incident took place in international waters in the South China Sea, about 75 miles south of Hainan Island.
U.S. officials said a protest was lodged with the Chinese government over the weekend and it was to be repeated to a Beijing military attache at a Pentagon meeting Monday.
The USNS Impeccable sprayed one ship with water from fire hoses to force it away. Despite the force of the water, Chinese crew members stripped to their underwear and continued closing within 25 feet, the Defense Department said.
"On March 8, 2009, five Chinese vessels shadowed and aggressively maneuvered in dangerously close proximity to USNS Impeccable, in an apparent coordinated effort to harass the U.S. ocean surveillance ship while it was conducting routine operations in international waters," the Pentagon statement said.
The Chinese ships included a Chinese Navy intelligence collection ship, a Bureau of Maritime Fisheries Patrol Vessel, a State Oceanographic Administration patrol vessel, and two small Chinese-flagged trawlers, officials said.
"The Chinese vessels surrounded USNS Impeccable, two of them closing to within 50 feet, waving Chinese flags and telling Impeccable to leave the area," officials said in the statement.
"Because the vessels' intentions were not known, Impeccable sprayed its fire hoses at one of the vessels in order to protect itself," the Defense statement said. "The Chinese crew members disrobed to their underwear and continued closing to within 25 feet."
Impeccable crew radioed to tell the Chinese ships that it was leaving the area and requested a safe path to navigate, the Pentagon said.
But shortly afterward, two of the Chinese ships stopped directly ahead of the Impeccable, forcing it to an emergency stop to avoid collision because the Chinese had dropped pieces of wood in the water directly in front of Impeccable's path.
"The unprofessional maneuvers by Chinese vessels violated the requirement under international law to operate with due regard for the rights and safety of other lawful users of the ocean," said Marine Maj. Stewart Upton, a Pentagon spokesman.
"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," Upton added.
In Beijing, Chinese officials did not immediately respond to voicemail messages and e-mail.
China views almost the entirety of the South China Sea as its territory. China's claims to small islets in the region have put it at odds with five governments -- the Philippines, Vietnam, Malaysia, Brunei and Taiwan.
Upton said U.S. Navy ships and aircraft routinely operate in the area and that Chinese ships and aircraft routinely steam or fly nearby. "However, these actions were considerably more aggressive and unprofessional than we have seen."
He said the Impeccable is one of five surveillance ships that gather underwater acoustical data.
The incident came just a week after China and the U.S. resumed military-to-military consultations following a five-month suspension over U.S. arms sales to Taiwan. And it came as Chinese Foreign Minister Yang Jiechi was due in Washington this week to meet with U.S. officials.
Pentagon officials said the close encounter followed several other incidents involving the Impeccable and another U.S. vessel Wednesday, Thursday and Saturday.