U.S. Secretary of State Rex Tillerson met Southeast Asian foreign ministers on Thursday to seek their support in pressing North Korea to give up its nuclear and missile programs.
Tillerson's first meeting with all members of the 10-nation Association of Southeast Asian Nations will also address another pressing regional issue - China's assertive pursuit of territory in the South China Sea, where several ASEAN members have competing claims.
Tillerson told reporters at the start of the Washington meeting that he and his counterparts would discuss North Korea.
Last week in the U.N. Security Council, Tillerson called on all U.N. members to fully implement U.N. sanctions on Pyongyang, which has ignored demands to abandon its weapons programs and is working to develop a nuclear-tipped missile capable of reaching the United States.
He also called on countries to suspend or downgrade diplomatic ties with Pyongyang, saying it abuses diplomatic privileges to help fund the arms programs. Tillerson warned countries that if they did not do so, Washington would sanction foreign firms and people conducting business with North Korea.
All ASEAN members have diplomatic relations with North Korea and five have embassies there.
The Trump administration wants Southeast Asian countries to crack down on money laundering and smuggling involving North Korea and restrict legal business too, U.S. officials said.
The administration has been working to persuade China, North Korea's neighbor and only major ally, to increase pressure on Pyongyang. U.S. officials say they are also asking China to use its influence with more China-friendly ASEAN members, such as Laos and Cambodia, to persuade them to do the same.
U.S. efforts have included a flurry of calls by President Donald Trump at the weekend to the leaders of the Philippines, Thailand and Singapore.
Diplomats say U.S. pressure has caused some irritation in ASEAN, including Malaysia, which has maintained relations with Pyongyang in spite of the assassination of North Korean leader Kim Jong Un's estranged half brother at Kuala Lumpur International airport on Feb. 13.
On the South China Sea, ASEAN has adopted a cautious approach recently toward China, with a weekend summit of its leaders avoiding references to Beijing's building and arming of islands there.
Analysts say this reflects concerns among some in the region that former U.S. President Barack Obama's "pivot" to Asia has been abandoned in favor of Trump's "America First" agenda, leading to more countries being pulled into Beijing's orbit.
(Reporting by David Brunnstrom; editing by Grant McCool)