(UPDATES) THE Department of Foreign Affairs (DFA) on Monday filed a diplomatic protest over the reported harassment of a Philippine Air Force (PAF) patrol aircraft when Chinese pilots dropped flares in the path of the PAF plane.

The Armed Forces of the Philippines (AFP) condemned the dangerous and provocative actions of the People's Liberation Army Air Force (PLAAF) that endangered the lives of its personnel undertaking maritime security operations recently within Philippine maritime zones.

"I was informed a diplomatic protest will be sent within the day," said DFA spokesman Ma. Teresita Daza on Monday when asked whether the government will protest the incident.

"On the question about the effect of the incident on the provisional understanding, please note the provisional understanding applies only to RoRe (rotation and resupply) missions in Ayungin Shoal," she said in a text message.

On August 8, PAF NC-212i aircraft was conducting a routine maritime patrol over Bajo de Masinloc when two aircraft from the PLAAF executed a dangerous maneuver at around 9 a.m. and dropped flares in the path of the NC-212i.

"The AFP has reported the incident to the DFA and relevant government agencies," AFP Chief of Staff Romeo Brawner Jr. said in a statement on Saturday.

In a statement on July 21, the DFA said the Philippines and China have reached an understanding on the "provisional arrangement" for the rotation and resupply missions to the beached BRP Sierra Madre in Ayungin (Second Thomas) Shoal in the West Philippine Sea (WPS).

"But the Philippines adopts a de-escalatory approach to tensions in the WPS. It remains committed to diplomacy and peaceful means of resolving disputes," Daza added.

"We reaffirm our commitment to exercise our rights in accordance with international law, particularly Unclos (United Nations Convention on the Law of the Sea) and the Chicago Convention," Brawner said.

He said the incident posed a threat to PAF aircraft and its crew, "interfered with lawful flight operations in airspace within Philippine sovereignty and jurisdiction, and contravened international law and regulations governing the safety of aviation."

"The pilots and crew of the NC-212i safely returned to Clark Air Base at 10:00 a.m. All personnel on board were unharmed," Brawner added.