Updated

Australian Prime Minister Malcolm Turnbull said Friday it is in China's best interests to curb the nuclear ambitions of North Korea, with which it shares a border.

By doing so, China will bring peace to the region and gain the trust of its neighbors after tensions over its territorial disputes in the South China Sea, he said at a security conference in Singapore.

China will "best succeed by respecting the sovereignty of others and in so doing, build a reservoir of trust and cooperation with its neighbors," Turnbull said. "And it has no better or more urgent opportunity to build that trust than to use its great leverage and the responsibility with which it comes to curb the unlawful, reckless and dangerous conduct of North Korea." China is North Korea's closest ally.

Beijing has pitted itself against its smaller neighbors in claiming disputed islands, coral reefs and lagoons in the South China Sea.

If the tensions persist, countries will decide to distance themselves from China and "look to counterweight Beijing's power by bolstering alliances and partnerships between themselves, and especially with the United States," he said.

Turnbull was opening the three-day security conference, known as the Shangri-La Dialogue. It is attended by defense ministers and experts from 39 countries, including U.S. Defense Secretary Jim Mattis.

Chinese officials are not scheduled to speak at the conference's main sessions. Organizers explained that they were keeping a low profile due to reshuffling before October's Communist Party Congress.

Eugene Tan, an associate law professor at the Singapore Management University, said the decision was a "conscious strategy."

"China has been very assertive, at times even aggressive, in the territorial disputes" in recent years, Tan told the AP. "This deliberate (soft) approach this year is not a back down at all. It's about not putting themselves in the spotlight."

Mattis is to chair a session on the role of the U.S. in Asia-Pacific security on Saturday. He is expected to echo traditional U.S. policy goals, including a strong global order and a peaceful, prosperous and free Asia.

The security conference is expected to focus on North Korea's nuclear ambitions and on Islamic extremism, including the fight against the Islamic State group.

On Friday, the group claimed one of its supporters carried out an attack on a casino in the Philippines in which 36 people died. The Philippine military has denied it was a terrorist attack.