Story highlights Philippines claims ownership of the Spratly Islands

Much of the chain is currently controlled by China

Hong Kong (CNN) Philippines President Rodrigo Duterte said Thursday he has ordered military personnel to occupy all Philippines-claimed islands in the disputed South China Sea.

"We tried to be friends with everybody but we have to maintain our jurisdiction now, at least the areas under our control. And I have ordered the armed forces to occupy all these," he said during a visit to a military camp on the Philippines island of Palawan.

Duterte said he may raise the Philippines flag on Pagasa Island, also known as Thitu Island, on the country's independence day on June 12.

Thitu is in the Spratly island chain, parts of which are claimed by the Philippines, China, Taiwan, Malaysia, Brunei and Vietnam.

Building up