In his visit to Asia, which he began on Sunday, U.S. Secretary of State John Kerry plans to press China to put more restrains on North Korea after its nuclear test and to urge Southeast Asia to respond to Beijing’s claims in the South China Sea in accord.

Kerry started a three-day stay in the region in Laos, the 2016 chair of the 10-member Association of Southeast Asian Nations (ASEAN). He plans on heading to Cambodia on Monday night and then on to Beijing for talks on Wednesday with the leadership there.

In Beijing, Kerry is expected to accentuate the need for a united front in response to this month’s North Korean nuclear test through additional U.N. sanctions, a senior official of the U.S. State Department said. He will also call for a strong unilateral response from China, North Korea’s main ally and neighbor.

“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 spending more effort.

On Jan.6, North Korea announced that it had successfully tested a hydrogen bomb. However, Washington expressed uncertainty as to whether the device was actually that powerful.
“North Korea is still engaged in illicit and proliferation activities,” the official 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 cause of mounting 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.