Defense Secretary Mattis welcomes Beijing's help on North Korea, prods on South China Sea

  • Mattis was speaking at Shangri-La Dialogue in Singapore.
  • Competition with China is bound to occur, but conflict not inevitable, he said.
  • South China Sea claims by Beijing rattle Washington, region.

Washington wants to work with Beijing on denuclearizing North Korea, but cannot accept China's actions in the South China Sea, U.S. Defense Secretary James Mattis said on Saturday in a speech that reflected the complex relationship between the world's two largest economies.

U.S. Defense Secretary James Mattis
Eric Thayer | Reuters
U.S. Defense Secretary James Mattis

Speaking at the Shangri-La Dialogue in Singapore, Mattis said President Donald Trump was encouraged by China's "renewed commitment to work with the international community" on ending the ballistic missile and nuclear weapons programs that North Korea shows no sign of abandoning.

Following the rogue nation's latest ballistic missile test last month, the U.N Security Council expanded sanctions against North Korean leader Kim Jong-un's regime on Friday while Trump's administration blacklisted several companies and people on Thursday for supporting Pyongyang's arms development.

Washington has urged Beijing to use its decades-old relationship with Pyongyang to apply more pressure on Kim – trade with China is a key source of revenue for North Korea's economy – amid a failure of international sanctions to halt Kim's missile tests.

Still, Trump's administration isn't holding back on criticizing the mainland.

"We cannot accept Chinese actions that impinge on the interests of the international community," Mathis said on Saturday, referring to the South China Sea conflict.

The world's second-largest economy claims 90 percent of the strategic waterway, home to over 250 islands and rich natural gas reserves, but Vietnam, Brunei, Malaysia, the Philippines and Taiwan also assert ownership of certain parts. And to the anger of other claimants, Beijing has been ramping up construction in the area— reports recently emerged of Chinese rocket launchers in the Spratly Islands.

Trump vowed to halt Beijing's construction of artificial islands days after taking office and despite the president's recent niceties with Chinese President Xi Jinping, the issue remains a sticking point the bilateral relationship. Last week, the Chinese navy deployed two missile frigates to a U.S. Navy warship that sailed near the China-claimed Spratly Islands.

"We oppose countries militarizing artificial islands and enforcing excessive maritime claims," Mattis stated. "We cannot and will not accept unilateral, coercive changes to the status quo."

Mattis also said he expected "friction" in the U.S.-China relationship, adding that "while competition between the U.S. and China is bound to occur, conflict is not inevitable."