BEIJING, China (CNN) -- A U.S. surveillance ship violated Chinese and international laws during patrols more than 100 miles (160 kilometers) off the Chinese coast over the weekend, China's state-run media reported Tuesday.
The Navy says this photo shows two Chinese trawlers forcing the Impeccable to make an emergency stop.
"China has lodged serious representations with the United States, as the USNS Impeccable conducted activities in China's special economic zone in the South China Sea," said Ma Zhaoxu, a Chinese Foreign Ministry spokesman. "We demand that the United States put an immediate stop to related activities and take effective measures to prevent similar acts from happening."
The response follows the Pentagon's contention Monday that Chinese ships harassed the U.S. vessel on Sunday in the latest of several instances of "increasingly aggressive conduct" in the past week.
During the incident, 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 said in a statement.
Ma said that "the U.S. claims are gravely in contravention of the facts and confuse black and white and they are totally unacceptable to China," although he didn't say what China's version of the events were.
According to the Pentagon, the Chinese crew members aboard the vessels, two of which were within 50 feet, waved Chinese flags and told the U.S. ship to leave the area.
"Because the vessels' intentions were not known, Impeccable sprayed its fire hoses at one of the vessels in order to protect itself," the Pentagon's statement said. "The Chinese crew members disrobed to their underwear and continued closing to within 25 feet." Watch CNN's Chris Lawrence report on the incident »
After the Impeccable alerted the Chinese ships "in a friendly manner" that it was seeking a safe path to depart the area, two of the Chinese ships stopped "directly ahead of USNS Impeccable, forcing Impeccable to conduct an emergency 'all stop' in order to avoid collision," the statement said.
"They dropped pieces of wood in the water directly in front of Impeccable's path."
A Pentagon spokesman called the incident "one of the most aggressive actions we've seen in some time. We will certainly let Chinese officials know of our displeasure at this reckless and dangerous maneuver."
He said the Chinese crew members used poles to try to snag the Impeccable's acoustic equipment in the water.
The U.S. Embassy in Beijing lodged a protest over the weekend with the Chinese government, a State Department spokesman said Monday.
The Impeccable's crew members are primarily civilians, and the ship is not armed, the spokesman said.
The 281.5-foot Impeccable is one of six surveillance ships that perform military survey operations, according to the Navy. It is an oceanographic ship that gathers underwater acoustic data, using sonar.
It has a maximum speed of 13 knots -- or about 15 mph -- but it travels 3 knots, or 3.5 mph, when towing its array of monitoring equipment. It carries a crew of 20 mariners, five technicians and as many as 20 Navy personnel.
The Chinese ships involved included a navy intelligence collection ship, a Bureau of Maritime Fisheries patrol vessel, a State Oceanographic Administration patrol vessel and two small Chinese-flagged trawlers, the statement said.
The Pentagon cited three previous instances of what it described as harassment, the first of which occurred last Wednesday.
CNN's Yuli Yang contributed to this report from Beijing.