The US military owns a number of reconnaissance aircraft developed on the basis of commercial aircraft and they often follow civil flights for cover when entering areas near China, a source close to the Chinese military said.

The US is said to have increased reconnaissance in the area near the southern coast of mainland China in recent weeks.

Sources close to the PLA said the E-8C reconnaissance plane was identified by the air traffic control radar system in Guangzhou province as a commercial aircraft flying at an altitude of more than 9,000 m over the East Sea.

`That risks causing accidents or misjudgments in the context of escalation between the US and Chinese militaries,` the source said.

US Air Force E-3C reconnaissance aircraft on duty, March 2015.

Lu Li-shih, a former instructor at the Taiwan Maritime Self-Defense Force training school in Kaohsiung, said many air forces and navies use `tricks` to hide their military activities.

`War allows deception. Some accidents have occurred when missile defense forces on the ground did not carefully confirm the identity of intruding aircraft,` Lu Li-shih said.

A Ukrainian Boeing 737 was shot down by Iran’s Islamic Revolutionary Guard Corps (IRGC) on January 7 after taking off from the capital Tehran, killing 176 people.

A similar accident occurred in September 1983, when a Soviet Su-15 interceptor shot down a Korean Air Lines Boeing 747 flying between New York and Seoul, killing 269 people.

Collin Koh, an expert at Singapore’s Institute of Strategic and Defense Studies, said all military and civil air traffic control units in the world use `identify friend-enemy` (IFF) signals.

`The E-8C is a large aircraft, the crew will care about safety in addition to successfully completing their mission,` Koh said.

Hong Kong-based military expert Song Zhongping said using civil aircraft platforms as reconnaissance aircraft not only saves costs but also facilitates missions.

`Almost all reconnaissance aircraft converted from large passenger aircraft do not carry weapons, but they can collect valuable military information and pose a direct threat to the PLA,` he said.

`US aircraft reconnaissance in the East Sea at night to monitor the PLA’s recent deployments of weapons and soldiers, because military mobilization activities often take place at night,` said expert Song Zhongping.

The E-8C is a reconnaissance aircraft model used by the US Air Force to manage combat and track targets on the ground.

In 2001, a PLA pilot died when a J-8II fighter collided with a US EP-3E reconnaissance aircraft operating near Hainan province, the southernmost tip of China.

The US 7th Fleet refused to comment on the night flights of the E-3C reconnaissance aircraft and said this was not a naval aircraft.