The Pentagon has revealed that at least two Chinese Shenyang J-11 fighter jets intercepted an American EP-3 reconnaissance aircraft over the South China Sea on Tuesday. The U.S. plane was on a routine mission in international airspace.

On Wednesday, a U.S. defense official told CNN that the Chinese jets came within 50 feet of the EP-3 during the incident. The official described the Chinese pilot’s behavior as “unsafe.”

Tech Times added that the American pilot was “forced to descend in order to avoid colliding with the other planes.”

Another defense official described the incident as unusual to CNN, saying the U.S. military does not usually see such provocative behavior from Chinese pilots in the region – unlike the increasingly belligerent conduct of Russian pilots in the Black Sea. In fact, the Defense Department has said Chinese practices have been generally improving over the past year.

The official said China “definitely has people’s attention” at the Pentagon after this stunt.

“This is potentially part of a disturbing trend line as the Chinese try to push their military envelope into greater parts of the sea surrounding their mainland,” Sen. Chris Murphy (D-CT), who sits on the Foreign Relations Committee, told CNN’s Wolf Blitzer in an interview.

“What the Chinese and the Russians are trying to do is to provoke us into some kind of action that will feed into their domestic narratives, both in China and in Russia,” Murphy added.

“The incident is just the latest escalation of tensions in and around the disputed SCS,” notes Jane’s 360, using an abbreviation for the South China Sea, adding:

Only a week earlier, on 10 May, China scrambled fighters to monitor USS William P Lawrence, an Arleigh Burke-class guided missile destroyer, as the warship was carrying out a so-called freedom-of-navigation operation (FONOP) within 12 n miles of Chinese-controlled Fiery Cross Reef in the Spratly Islands chain.

“The United States will fly, sail and operate wherever international law allows. That is true in the South China Sea as in other places around the globe,” declared Pentagon spokesman Cmdr. Bill Urban, as quoted by Tech Times.

China continued its practice of blaming all confrontations on the United States, which it accuses of “militarizing” the South China Sea.

“It needs to be pointed out that American aircraft have constantly entered China’s coastal waters conducting reconnaissance, which has posed a serious threat to China’s maritime and air safety,” said Ministry of Foreign Affairs spokesman Hong Lei. “We hereby ask the U.S. immediately to stop these actions so as to avoid the recurrence of such incidents.”

CNN reports that Beijing also insisted its pilots “kept a safe distance throughout” the encounter, “without taking any dangerous actions.”