China, being a "friend" of the Philippines, should at least have extended "courtesy" when its warships entered the country's exclusive economic zone, Malacañang said on Friday.

In an interview, Presidential Spokesperson Salvador Panelo said that the Palace supports the statement of Defense Secretary Delfin Lorenzana that when a ship of another country passes through an EEZ of another country, it should seek permission.

"We’re friends," Panelo said of the Palace's message to China after its warships entered Philippine EEZ several times without permission, adding that as friends, "we provide each other with courtesies required of friendship."

According to Lorenzana, Chinese warships passed through Sibutu Strait four times between February and July without informing or seeking permission from the Philippines.

But at the same time, Panelo was giving the Chinese government the benefit of the doubt it was not aware of the actions of its warships.

"We do not know actually if the Chinese government allowed this kind of violation because it may be that warships pass through that (area) without the Chinese government knowing it,” he said.

He said there could have been "negligence on the part of those in command."

The Philippines filed a diplomatic protest with Beijing over the matter.

The Philippines and China have been embroiled in a territorial dispute in the South China Sea.

President Rodrigo Duterte is set to go to China later this month to discuss with his Chinese counterpart, President Xi Jinping, the South China Sea issue. Celerina Monte/DMS