WASHINGTON — Secretary of State Rex Tillerson on Thursday pressed Southeast Asian governments to ensure “leak-proof” enforcement of sanctions against North Korea and to prevent the pariah nation’s diplomats from conducting business that could benefit its weapons programs.

Tillerson called on foreign ministers of the 10-nation Association of Southeast Asian Nations, or ASEAN, to “minimize” the diplomatic relations with Pyongyang, “so that North Korea does not gain benefit from its diplomatic channels for its nuclear and missile aspirations,” senior State Department official Patrick Murphy said after Thursday’s meeting at the State Department.

That was the latest salvo in the Trump administration’s push to get the international community to intensify diplomatic and economic pressure on North Korea to dismantle its nuclear weapons program before it can pose a direct threat to the American mainland.

Although China, North Korea’s traditional ally and main trading partner, is viewed as the key lever of international influence, Southeast Asian nations have diplomatic relationships with Pyongyang and small-scale trade ties, and have sometimes served as conduits for North Korean activities that violate U.N. sanctions. A recent U.N. report found that North Korean diplomats often play key roles in commercial activities banned under Security Council resolutions aimed at starving it of technology and revenue for its nuclear and missile programs.

“North Korea in many countries has a diplomatic presence that clearly exceeds their diplomatic needs,” Murphy told reporters.

He said, without providing specifics, that “considerable common ground was identified” between the U.S. and ASEAN on North Korea. He said that the February assassination of North Korean leader Kim Jong Un’s estranged brother at a Malaysian airport, using a chemical agent, illustrated the threat it posed “in the heart of ASEAN.” He said this has galvanized concern in the region.

Enrique Manalo, acting foreign secretary of the Philippines, said the way forward with North Korea was through dialogue and de-escalation of tensions. He said China has an “important role” to play, and ASEAN has not really yet discussed reducing the presence of North Korean diplomatic presence in their countries.

“That’s probably something we’ll look at,” Manalo told reporters. “Our immediate concern is that the tension in the (Korean) peninsula does not increase, because the more it increases the more danger of some kind of miscalculation. The last thing we would really like to see is to have a conflict break out.”

Southeast Asia’s top diplomats are clearly seeking better ties with Washington, amid uncertainty over the Trump administration’s trade policy and its dealings with China. They have been heartened by President Donald Trump’s plans to attend an ASEAN-hosted summit in the Philippines in November and a regional economic summit in Vietnam.

Eight foreign ministers and two other senior officials from the 10 nations traveled across the world for the face-to-face with Tillerson. Broadly speaking, they want a sustained U.S. presence in the region – which President Barack Obama promised them as part of his “pivot” to Asia – to counter China’s military assertiveness and growing economic dominance over its neighbors.

“We had a very good meeting: short, sharp and to the point,” Singaporean Foreign Minister Vivian Balakrishnan told reporters. He emphasized the importance of economic and trade ties between the U.S. and Southeast Asia.

However, long-standing U.S. allies like the Philippines and Thailand have moved closer to China, complicating U.S. hopes for unity on issues like control over the potentially resource-rich South China Sea. The Philippines, which is currently chair of ASEAN, has dialed back its once strong stance over China’s assertive behavior and island-building.

Murphy said the U.S. remains committed to freedom of navigation and commerce in the South China Sea. He said Tillerson had urged all “relevant parties” to stop militarization, construction and reclamation there while ASEAN and China conduct talks – which have dragged on for years – aimed at framing a binding code of conduct to prevent conflict.

Trump has feted Chinese President Xi Jinping as he pushes for more cooperation against North Korea. Southeast Asian nations generally welcome cordial ties between the two powers but worry about whether secret deal-making might undercut Washington’s willingness to stand up to China, which claims virtually all the South China Sea and has conflicting territorial claims with four ASEAN nations.

Story: Matthew Pennington