DAVAO CITY -- President Rodrigo Duterte on Sunday insisted on Southeast Asia's decades-old policy of "non-interference" in what appeared to be a swipe at the United States as the Philippines hosts the regional summit this year.

Duterte cited the 1976 Treaty of Amity and Cooperation where the 10-member Association of Southeast Asian Nations (ASEAN) agreed on "non-interference in the internal affairs of one another."

"I also call on ASEAN Dialogue Partners to renew their dedication to the valued purposes and principles stated in the Treaty of Amity and Cooperation -- including non-interference -- in promoting regional peace and stability through abiding respect for the rule of law," he said during the launch of ASEAN 2017 here.

"Now, more than ever, it is a time for real change through constructive engagements."

A dialogue partner of ASEAN accounting for 8 percent of the region's total trade, the US has been heavily criticized by Duterte for sounding the alarm on his bloody crackdown on illegal drugs.

Chinese Ambassador Zhao Jianhua on Sunday said Duterte's insistence on "non-interference" did not necessarily favor Beijing, the regional bloc's top trading partner.

"I wouldn't put it that way," he told reporters here. "We appreciate that ASEAN has been developing the ASEAN way, which is characterized by non-interference and by doing things by consensus."

Zhao welcomed the Philippines' decision to set aside its arbitral victory during ASEAN meetings this year.

"I like it very much," he told reporters, but insisted Beijing did not ask Manila to come to this decision.

"No. We respect the Philippines' position in that regard," he said.

Foreign Affairs Undersecretary Enrique Manalo earlier said the Hague ruling need not be included in this year's ASEAN agenda because "it’s already part of international law."

But last year, the Philippines unsuccessfully pushed the regional bloc to refer to the ruling in its joint communique in Laos. China's ally Cambodia blocked the move.