Philippine President Rodrigo Duterte warned Southeast Asian leaders on Saturday they were facing a "massive" illegal drug menace that could destroy their societies, as he called for a united response.
Duterte, who has faced international condemnation for his own crackdown on drugs that has claimed thousands of lives, also insisted that outsiders should not interfere in Southeast Asia's affairs.
"The illegal drug trade is massive but it is not impregnable," Duterte said in a speech to open an Association of Southeast Asian Nations (ASEAN) leaders summit.
"With political will and cooperation, it can be dismantled. It can be destroyed before it destroys our societies."
Duterte urged the leaders to be "resolute in realising a drug-free ASEAN".
Duterte has relentlessly railed against criticism of his drug war, which Amnesty International and other rights groups have warned may amount to a crime against humanity.
Duterte has said he is "happy to slaughter" millions of addicts in his quest to stop the Philippines from becoming a narco-state, and that human rights cannot stand in the way of eradicating drugs.
Police have reported killing 2,724 people as part of Duterte's anti-drug campaign, although authorities insist the shootings have been in self-defence.
Many thousands of others have been killed by shadowy vigilantes, according to rights groups.
A Filipino lawyer filed a complaint this week against Duterte at the International Criminal Court, accusing him of "mass murder" and alleging that as many as 8,000 people had died in the drug war.
In his speech to ASEAN leaders, Duterte highlighted the bloc's tradition of "non-interference".
He did this while talking about relations with the United States and the European Union, which have expressed concern about alleged extrajudicial killings in his drug war.
"Dialogue relations can be made more productive, constructive if the valued principle of non-interference in the internal affairs of the ASEAN member-states is observed," Duterte said.
Rights groups said in the lead-up to the summit that ASEAN leaders were unlikely to criticise Duterte, with Human Rights Watch calling the bloc "a club of cosy dictators or rights abusers".
Among the heads of undemocratic regimes in Manila are Thai military junta chief Prayut Chan-O-Cha, Cambodia's Hun Sen, a former Khmer Rouge cadre, and Sultan Hassanal Bolkiah of Brunei.
Some ASEAN leaders expressed support for Duterte and his drug war in Manila.
"We also share your country's concerns on the devastating effects of drugs upon society and I understand your personal resolve in combating it," Bolkiah said as Duterte hosted him at the presidential palace on Thursday.