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 did n'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 .
China says China surveillance ship conducted activities in a `` special economic zone '' U.S. demands U.S. take measures `` to prevent similar acts from happening '' Pentagon says Chinese ships harassed Pentagon Impeccable in international waters . Chinese crew tried to snag Impeccable 's equipment in water , USNS says .