US Secretary of State John Kerry begins a visit to East Asia on Sunday in which he plans to press China to put more curbs on North Korea after its nuclear test and to urge Southeast Asia to show unity in response to China's claims in the South China Sea.
Kerry starts what will be a three-day stay in the region in Laos, the 2016 chair the 10-member Association of Southeast Asian Nations (ASEAN), after attending the Davos summit in Switzerland and a stop in Saudi Arabia.
He will head to Cambodia on Monday night and then on to Beijing for talks on Wednesday with the leadership there.
In Beijing, Kerry is expected to stress the need for a united front in response to this month's North Korean nuclear test through additional U.N. sanctions and for a tough unilateral response from China, North Korea's main ally and neighbor, a senior official of the U.S. state Department said.
"It is very important to present a united front ... but that united front has to be a firm one, not a flaccid one," the official told journalists traveling with Kerry.
It was particularly important to "cut off avenues of proliferation and retard North Korea’s ability to gain the wherewithal to advance its nuclear and its missile programs," the official said, and that meant China doing more.
"North Korea is still engaged in illicit and proliferation activities," he said. "They have very few avenues for conducting business with the international community that don’t in some fashion involve transiting China.
"Despite the determination and efforts of the Chinese government, clearly there is more that they can do."
In Beijing Kerry plans "in depth" discussions on the South China Sea, a source of increasing tension between China and ASEAN countries and the United States due to China's building of artificial islands suitable for use as military bases, the official said.
First though in Vientiane, Kerry will seek to bolster ASEAN unity and the bloc's resolve to stand up to China in the lead up to a summit President Barack Obama has called with the bloc's leaders for Feb. 15-16 in Sunnylands, California.
Laos has close political and economic ties with its giant neighbor China, worrying the Obama administration that Vientiane might behave like Cambodia did it held the ASEAN chair in 2012, and was accused of obstructing consensus in the bloc over the South China Sea.
Besides its China ties, as a landlocked country Laos has less interest in the maritime disputes that several ASEAN members have with Beijing.
The US official said he had heard from virtually every ASEAN country that the Cambodian chairmanship had left "a black mark" on the bloc that was not to be repeated.
So far, Laos was off to a good start overseeing ASEAN statements on world events, the official said, adding: "It's my expectation that the Lao will be a responsible chair for 2016."
Kerry will seek to set an encouraging tone in Laos by discussing increased US aid, including more funding for work to dispose of unexploded US ordnance left over from the Vietnam War, when Laos became one of the most heavily bombed countries in history as the United States sought to destroy communist supply lines running through it.
The main actual announcements are expected though to come when Barack Obama becomes the first US president ever to visit the country when he attends a regional summit towards the end of the year.
In Cambodia, Kerry will meet Hun Sen, now Asia's longest serving prime minister, and will draw attention to US concerns about human rights and treatment of government critics by meeting opposition members and civil activists, the State Department official said.