MANILA (UPDATE) - President Rodrigo Duterte on Monday issued a call to action against terrorism and illegal drugs as he opened an international meeting among regional leaders, including the world's superpowers.

Duterte on Monday formally opened the 31st Association of Southeast Asian Nations Summit, which gathered leaders of the 10-nation regional bloc and dialogue partners, including the United States and China, for 2 days of meetings.

In his speech, Duterte cited the five-month siege in Marawi City, which Islamic State-inspired terrorists had attempted to capture in a bid to establish a stronghold in the Philippines and in the region.

"I apologize for setting the tone of my statement in such a manner. But I only want to emphasize that our meetings for the next two days present an excellent opportunity for us to engage in meaningful discussion on matters of regional and international importance,” Duterte said in his speech.

"Terrorism and violent extremism endanger peace, stability, and security of our region, because these threats know no boundaries. Piracy and armed robbery put a dent on our growth and disrupt the stability of both regional and global commerce.”

The Marawi crisis, which ended on Oct. 23, left over 1,000 people dead, mostly terrorists, and hundreds of thousands displaced. It also left the city, considered one of the centers of Islamic faith in Mindanao, in ruins.

• Gov't to count war wounds in Marawi's main battle zone

With the massive devastation left by the siege and the large number of fatalities on the side of the terrorists, the President had on Sunday said both sides “got nothing” from the siege.

• Duterte: Nobody won the war in Marawi

In his speech, Duterte thanked countries that extended relief and military assistance as the Philippines sought to end the Marawi crisis.

"Resolute, we are now in the process of helping people back on their feet to reclaim their lives,” he said.

The Marawi siege, the Philippines’ biggest security problem in years, sparked concerns that the Islamic State has started building a new base in Southeast Asia as its fighters suffered heavy losses in Syria and Iraq.

DUTERTE: DRUG MENACE THREATENS SOCIAL FABRIC

In his speech, Duterte also cited the illegal drug problem. The President’s war against drugs has attracted international criticism over thousands of killings and alleged abuses.

"The menace of [the] illegal drug trade continues to endanger the very fabric of our societies,” he said.

The Duterte administration has many times defended the drug war, saying it does not condone police abuses nor sanction summary killings.

• Duterte takes hands-off approach on drug war

Government has said over 3,800 were killed in legitimate anti-illegal drug operations, while human rights groups peg the number of deaths at over 13,000.

Duterte recently scaled back his campaign against illegal drugs, tapping the smaller Philippine Drug Enforcement Agency as the lead government body to enforce the campaign and relegating the police force to a supporting role.

• Duterte: PDEA should lead anti-illegal drug ops

Also in his welcome speech, Duterte announced the upcoming signing of a landmark document aimed at improving the conditions of Southeast Asia's migrant workers.

The document, titled ASEAN Consensus on the Protection and Promotion of the Rights of Migrant Workers, seeks to “strengthen social protection, access to justice, humane and fair treatment, and access to health services” for the region's overseas workers.