China on Wednesday lodged a diplomatic protest with the United States, raising objection over its second spy plane, which it said, 'intruded' into its 'no-fly zone' to snoop over the ongoing military exercises by the Chinese military in the disputed South China Sea.
A US RC-135S reconnaissance aircraft on Wednesday flew near the ongoing Chinese People's Liberation Army (PLA) drills in the South China Sea, a day after another US spy plane, a U-2, trespassed into another PLA exercise restricted zone, state-run Global Times reported.
The US is increasing the frequency of its close-up reconnaissance of PLA drills in order to pry about the PLA's capabilities, which is provocative, and brings the risk of accidents and could lead to escalation, Chinese experts said.
The US, which is piling up pressure on China on trade and diplomatic fronts during the past few months, also stepped up air and naval patrols in the South China Sea where USS Nimitz and USS Ronald Reagan Carrier Strike Groups conducted dual-carrier operations last month in a show of strength.
The RC-135S is designed to gather data on ballistic missile launches, re-entry and electronic information, which means the US might believe the PLA was conducting live-fire anti-ship ballistic missile exercises in the South China Sea, the report quoted Chinese defence experts as saying.
The Chinese military said in a statement that the US reconnaissance planes' activities 'seriously interfered in normal exercise activities' and 'severely incurred the risk of misjudgement and even of bringing about an unintended air-sea incident'.
Chinese Foreign Ministry spokesman Zhao Lijian said that China has lodged a diplomatic protest with the US over the planes' intrusion into China's no-fly zone.
"I'd like to stress that the US' U-2 high altitude reconnaissance plane arbitrarily intruded into the no-fly zone for live-fire exercises by the Northern Theatre Command of the PLA," he told a media briefing, stating that planes flew over China's sovereign territory.
China claims sovereignty over most part of the resource-rich South China Sea.
However, the Philippines, Vietnam, Malaysia, Brunei and Taiwan have counter claims.
The US has been pressing its naval vessels and military planes over the area to assert the freedom of navigation, rejecting China's claims over sovereignty.
Zhao said that 'the trespass severely affected China's normal exercises and training activities, and violated the rules of behaviour for air and maritime safety between China and the US as well as relevant international practices'.
"It could easily have resulted in misjudgements and even accidents. China firmly opposes such blatant provocation and has lodged stern representations with the US.
"We urge the US to immediately stop such provocative moves and take real actions to uphold regional peace and stability," he said.
The PLA drills are being held in the waters from Monday to Saturday, according to a navigation restriction notice released by the Hainan Maritime Safety Administration on Friday, which did not provide further details.
China usually tests ballistic missiles inland to keep confidential intelligence away from other countries, and the PLA also has many other types of exercise subjects that it conducts in the South China Sea, so the ongoing drills do not necessarily feature anti-ship ballistic missiles, Chinese military experts added.