On-board footage posted by PTV on social media appeared to show the Chinese jet making a turn at a higher altitude than the Cessna with multiple missiles visible, signalling it was on a combat-capable mission.
The Russian-made Su-30 is a multirole fighter, mainly used for long-range interception, strike and air superiority missions.
A PTV reporter on board the Cessna Caravan said the jet tailed the single-propeller coastguard plane for about 20 minutes and allegedly conducted “dangerous manoeuvres” at close proximity, an estimated “200 to 500 feet (30 to 150 metres)” away.
Meanwhile, People’s Liberation Army Navy ships in the area repeatedly issued radio challenges during the incident, according to the report, and a communication from a US Navy ship was also heard.