DAVAO CITY (UPDATE) - A Chinese maritime tracking ship docked at Sasa Wharf Friday to refuel and restock the crew's food supply, the Philippine Coast Guard (PCG) said.

The ship's crew members will also go on an organized tour in the city, according to PCG Davao Commander George Maganto.

He added that the Chinese staff submitted a letter of intent for a goodwill visit in the city in January, and was approved by the Department of Foreign Affairs (DFA) last August 23.

Though the ship is a research vessel, Maganto said they are not allowed to conduct research within the Philippine jurisdiction.

"Yes they have radars, navigational equipments but base on the clearance permitted to us, kapag nandito sila sa area ng Pilipinas they are not allowed to conduct research in the Philippine territory," he said.

The ship will stay in the city until September 3.

This is the 5th time a Chinese vessel visited the country since President Rodrigo Duterte came into power.

A Chinese research ship docked in the hometown of Duterte on July 16 for a goodwill visit.

• Chinese research ship docks in Davao City

Chinese envoy Zhao Jianhua earlier said there were no special considerations made for the ship and two Chinese military planes that arrived in the city in June.

• No special considerations for Chinese planes that landed in Davao, says envoy

"We do that in accordance with the requirements for approval by (the) department concerned in the Philippines. The plane landed in Davao and the ship visited to Davao are all permitted by the Philippine authorities," he told reporters after the Asia-Pacific Healthy Islands Conference 2018.

• Gov't confirms Chinese military plane landed in PH to refuel
• K: Another Chinese aircraft lands in Davao City to refuel, Air Force unit confirms

--Report from Berchan Louie Angchay, ABS-CBN News