MANILA (BLOOMBERG) - Philippine President Rodrigo Duterte is maintaining a friendly tone towards China, even after defence officials raised concerns over an increased Chinese presence around a disputed island in the South China Sea.

China isn't after Philippine territory and hasn't asked for anything in exchange for the weapons and aid it has given the Philippines, Mr Duterte said in a campaign speech in Manila late on Tuesday (April 2).

"You know, Red China or Communist China just wants to be friends with us," Mr Duterte said. He added that he wouldn't confront China over the two countries' competing territorial claims in the South China Sea because it would result in war.

More than 200 Chinese ships have been spotted near the Philippine-occupied Thitu Island in the South China Sea since the start of the year, triggering a diplomatic protest from the Philippines.

Defence Secretary Delfin Lorenzana earlier this week voiced alarm over China's actions in the sea, describing Beijing's island-building activity in waters claimed by Manila as "very concerning" after meeting his acting US counterpart Patrick Shanahan at the Pentagon, the Philippine Daily Inquirer reported.