MANILA- China is "gravely concerned" and "dissatisfied" with Defense Chief Delfin Lorenzana's visit with other Philippine military officials to Pag-asa Island on Friday.

Chinese Foreign Ministry Spokesperson Lu Kang on Friday said the visit runs against the consensus reached by Manila and Beijing "to properly deal with the South China Sea issue."

It said the Philippines could instead "cherish the hard-won sound momentum" on bilateral ties of the two countries, which has seen a turnaround since President Duterte took office.

"This move runs counter to the important consensus reached between the two leadership which is to properly deal with the South China Sea issue. Gravely concerned about and dissatisfied with this, China has lodged representations with the Philippine side," Lu said.

His remarks were posted on the Chinese Foreign Ministry website.

The defense chief on Friday flew to Pag-asa Island to inspect its facilities, some of which are in dire need of repair. Lorenzana added that the Duterte administration is also asserting its claim over the area.

"This is just a normal visit within our territory, which we believe and we know is (our) territory," Lorenzana told reporters who accompanied him on the brief trip.

Lu added that since President Rodrigo Duterte's visit to China last year, both countries have been keeping "good communication on properly managing and resolving maritime issues."

"We hope that this momentum can continue. We hope that the Philippines can work with China to jointly maintain regional peace and stability as well as the sound momentum of moving bilateral relations forward," Lu said.

China challenged 2 Philippine planes, one of which was carrying Lorenzana, as it approached Pag-asa island, in the West Philippine Sea, the Philippines' exclusive economic zone in the disputed South China Sea.

The Philippine planes were told to stay away from the area where the Chinese-controlled Subi reef is also located.

Lorenzana however downplayed the incident as part of "protocol."

"That's their protocol. That's procedural. We also reply that we are flying over Philippine territory," he said.

The Philippines and China are set to hold bilateral talks on the dispute in May.