The People's Liberation Army (PLA) Air Force Friday scrambled fighter jets to identify US and Japanese military aircraft in China's newly established Air Defense Identification Zone (ADIZ) over the East China Sea.

According to a statement posted on the website of China's defense ministry, Shen Jinke, spokesperson of the Air Force, said fighter jets including Su-30 and J-11 were scrambled Friday morning to the zone. The Chinese jets identified two US reconnaissance aircraft, a P-3 and an EP-3, as well as 10 Japanese jets coming in seven batches, including the models E-767, P-3 and F-15.

Shen said the PLA Air Force has been working with the PLA Navy to monitor the entire process of foreign military jets' entering of the ADIZ and identify them in a timely manner.

Friday's mission by Chinese fighter jets realized China's regular and effective monitoring and control of the ADIZ, said the air force spokesperson.

It was the second time that China announced its fighter jet mission in the ADIZ since two unarmed US B-52 bombers flew into the zone without notifying China on Tuesday, after which China's defense military said in a statement that it had monitored the whole process.

Following the US defiance, aircraft from the South Korean military and Japanese coast guard and military made similar moves.

On Thursday, the PLA Air Force sent several fighter jets and an early warning plane to patrol the zone.

Li Jie, a military expert, told the Global Times on Friday that the PLA Air Force's announcement of Friday's mission is a response adjusted according to recent occurrences.

"It is nothing new that foreign aircraft such as US EP-3 scout planes fly close to China and we think it is unnecessary to release what we have monitored every time, by which we mean to save some face for these countries," Li said.

"But given the defiant moves from the US and Japan in the past week, we announced their intrusions to warn other countries, particularly the US and Japan, that China has the capability and techniques to monitor their moves within the zone and they may not act too aggressively," he said.

Regarding the PLA Air Force's patrol in the ADIZ, Qin Gang, China's foreign ministry spokesperson, Friday told a regular press briefing that planes from the Air Force have the right to patrol in the zone in light of the need of air defense.

Qin said China's armed forces shoulder the mission of protecting the country and safeguarding peace, noting that the armed forces are permanently on a state of high alert, the Xinhua News Agency reported.

Meanwhile, the US and Japan went ahead with a massive naval exercise, AnnualEx 2013, with the USS George Washington, a 90,000-ton Nimitz-class aircraft carrier, patrolling waters off the island of Okinawa, CNN reported.

The drill involves dozens of warships, submarines and aircraft from the US Navy's 7th Fleet and the Japan Maritime Self Defense Force, according to CNN.

CNN quoted the US Navy as saying that the drill aims to provide a stern test of their ability to effectively and mutually respond to the defense of Japan or to a regional crisis or contingency situation in the Indo-Asia-Pacific region.

"Our operations in the East China Sea will continue as they always have," Vice Admiral Robert Thomas, commander of the US 7th Fleet, told reporters Thursday, when asked about China's ADIZ, the Asahi Shimbun reported.

According to the report, commenting on China's ADIZ, Vice Admiral Yasushi Matsushita, commander of the Self Defense Fleet, said, "While we will have to be more cautious than before, I do not believe we have to limit our activities."