MANILA -- Defense Secretary Delfin Lorenzana is not buying the explanation of the Chinese government that its survey ships were only passing by Benham Rise, and not conducting any surveying activity.

Lorenzana last Thursday said satellite photos and incident reports indicate that China had sent a ship to Benham Rise.

He said Chinese ships have no business in these waters and that Beijing’s defense of the act as an “innocent passage” contradicts what he saw.

"As far as we are concerned, they have no business going there kasi kung innocent passage sana yun, 'alam niyo naman ang innocent passage from Point A to Point B, dire-diretso lang 'yon at constant 'yung steaming speed. Eh 'yung nakita natin is 'yung survey ship napakabagal eh. Tapos tumitigil sa isang lugar, magtatagal doon ng ilang araw, lipat naman sa kabilang lugar. So that is not innocent passage," Lorenzana said.

(What we saw is that the survey ship was very slow and was stopping at some places and will stay there for a few days then transfer to another place.)

China's Foreign Ministry spokesman, Geng Shuang on Friday dismissed concerns expressed by Lorenzana over what he believes was surveying activities being done by China.

The Chinese spokesman said its ships had every right of freedom of navigation in those waters, and its research ships did pass through seas northeast of Luzon island last year.

"But this is purely carrying out normal freedom of navigation and right of innocent passage, and there were no so-called other activities or operations," he told a regular news briefing.

• READ: China dismisses Philippine concerns over its ships' activities

Lorenzana, however, noted that he still trusts what China says but Philippine military forces will continue to patrol the country’s area to see if Chinese ships are still going there.

The Defense chief said the presence of Chinese survey ships has been elevated to the discussion of the National Security Council.

"We are actually worried, kasi nung nakita natin last year na pa-ekis ekis 'yung mga survey ship, naalarma kami. Pinagusapan namin ni National Security Adviser (Hermogenes) Esperon, prinesent namin sa security council 'yun," he said.

(When we saw that the ships were crisscrossing last year. We were alarmed. I discussed it with National Security Adviser Esperon and we presented it to the security council.)

The Defense Department and the Armed Forces will also take new steps to further protect Benham Rise from incursion.

"We will do something there. Siguro we will increase our patrols, at the same time, siguro we will put something there, a structure to say this is ours," Lorenzana said.

He said President Rodrigo Duterte echoed their recommendations, contrary to the belief of some that the President was too soft on China.

Lorenzana quoted Duterte as saying: “Let us increase 'yung mga patrol natin, para mapakita naman natin sa ibang tao na we have jurisdiction over those areas.”

(Let us increase our patrols so we can show other people that we have jurisdiction over those areas.)

The Department of Foreign Affairs (DFA) last Friday said it has already sent a note to the Chinese embassy seeking clarification over the reported arrival of a Chinese survey ship in Benham Rise.

“The Philippines has sent a note to the Chinese Embassy seeking clarification on this.”

Benham rise is the latest addition to Philippine territory, a massive 13-million hectare expanse of sea area that was awarded to the country by the United Nations in 2012 after the Philippines successfully proved that it is part of Isabela province's extended continental shelf.

Though largely still unexplored, Benham Rise is believed to be rich in oil and natural gas deposits, apart from the marine life that may be exploited from there. -- with a report from Reuters