Ahead of this week's G-20 summit in Hamburg, Germany, Donald Trump called the leaders of China and Japan to discuss the "threat posed by North Korea', along with trade issues, the White House said on Sunday. Trump spoke with Chinese President Xi Jinping and Japanese Prime Minister Shinzo Abe, whose LDP had just suffered a devastating loss in the Tokyo Assembly elections, and according to the White House read out, "both leaders reaffirmed their commitment to a denuclearized Korean Peninsula" adding that "President Trump reiterated his determination to seek more balanced trade relations with America's trading partners."

The terse statement did not provide further details of the call or say if Trump managed to persuade Xi to endorse his approach of exerting maximum pressure on North Korea, including a slew of further economic and trade sanctions.

According to Reuters, the call may have been prompted by Trump increasing frustration with China's inability to rein in North Korea, and the reference to trade was an indication the president may be ready to return to his tougher-talking ways on business with Beijing after holding back in hopes it would put more pressure on Pyongyang. Trump and Xi discussed the "peace and stability of the Korean peninsula", China's Foreign Ministry said, without elaborating.

Ministry spokesman Geng Shuang later told a daily briefing that the United States was "very clear" about China's position on North Korea. Geng did not elaborate on what Xi told Trump about North Korea.

And while Trump may have been pushing for another PR push to demonstrate that he is on top of the N. Korea situation, what he got in return was a clear debuke from President Xi Jinping, who urged Trump to abide by Washington's decades-old "one-China" policy during the phone call "as tensions between the two countries resurfaced over Taiwan, disputes in the South China Sea and how to handle North Korea's nuclear weapons programme" SCMP reported.

Confirming that US-Sino relations have deteriorated substantially in recent weeks, Xi issued an implied warning to the US president, saying US-China relations have been affected by "negative factors" since the two men met for the first time at the Mar-a-Lago summit in Florida in April, the state broadcaster China Central Television reported.

"We attach great importance to the US government's reaffirmation of the one-China policy and hope the US side will properly handle the Taiwan problem by adhering to the one-China principle and the three communiqués between the two sides," Xi was quoted as saying. The call came after the Trump administration agreed a US$1.4 billion arms sales package with Taiwan, which China slammed over the weekend.

In the past week, diplomatic realtions between China and the US have chilled substantially, after Beijing lodged protests following Washington's announcement of the Trump administration's first arms sales to Taiwan. China has also protested against the blacklisting of a small Chinese bank accused of illicit dealings with North Korea.

Beijing was further infuriated last week with a bill approved by the US Senate Armed Services Committee that would allow regular stops by American naval vessels to Taiwan's ports. Tensions have also been raised between the two countries over China's assertive claims to islands in the South China Sea.

Adding to Beijin's anger, on Sunday, the USS Stethem, a guided-missile destroyer, sailed within 12 nautical miles of Triton Island, part of the Paracel Islands in the South China Sea, to which China responded by dispatching military vessels and fighter jets to intercept the US warship. Analysts quotedb y SCMP said Beijing may in future have to deal with a more confrontational approach from the Trump administration, which appears to be using Taiwan as leverage against Beijing.