On the call, Mr Xi reminded the American leader the two countries had agreed to keep close communication on the issue. The fickle Florida "bromance" three months ago between Trump and Xi is dead and the leaders of the world's two biggest economies and military powers are poised for a testy dialogue. Credit:AP Mr Xi made the phone call at the request of President Trump and both sides were candid in their opinions, according to the Chinese Foreign Ministry. At a Wednesday afternoon press conference, when asked to comment on the US aircraft carrier USS Carl Vinson heading to Korean waters, a Chinese Foreign Ministry spokesman said: "we hope all parties refrain from irresponsible actions that would be very dangerous at the moment". Chinese officials have publicly said any response to a nuclear test must be made through the United Nations Security Council, amid indications China would vote in favour of tougher sanctions against North Korea.

In a sign North Korea may be ready to improve its international engagement, Supreme People's Assembly on Tuesday revived a parliamentary foreign affairs committee which was disbanded in 1998. Korean Central News Agency reported that a former diplomat, Ri Su-yong was appointed to head the Diplomatic Commission. An F/A-18 fighter prepares to take off from the deck of the aircraft carrier USS Carl Vinson at an unidentified location in the international waters, east of the Korean Peninsula. Credit:AP North Korea watchers in Beijing said they believed a missile intercept by the United States was a more likely response to a North Korean missile test than the US making a direct attack on North Korean soil. Associate professor Cai Jian, an expert on North Korea at Shanghai's Fudan University, said "If there is an interception, it won't cause much conflict. It may escalate tension but is different to direct military attack". An American soldier stands guard during the US-South Korea joint exercise in Pohang, South Korea, last Tuesday. Credit:AP

He said the consequences of a missile intercept would be similar to minor military conflicts between North and South Korea "and will be under control". But Mr Cai questioned whether North Korea would conduct a nuclear test when the US and China appeared to be cooperating on the issue of North Korean denuclearisation. North Korean leader Kim Jong-un will feel secure from invasion only once he has the capacity to strike the US. Credit:KRT North Korea's weapons program and behaviour weren't in China's strategic interest, he said, and China needed to take further action, which could include cutting North Korea's oil supply. A 30-kilometre long Chinese oil pipeline from Dandong in northern China to North Korea carries 520,000 tonnes of crude oil a year, but it is not recorded in customs records and technically avoids breaching UN sanctions on North Korea because it is classed by China as "aid".

In recent days, Chinese customs have tightened checks on cargo trucks entering China from North Korea, and at sea, multiple North Korean coal tankers have been turned away from Chinese ports after the Chinese government banned companies from accepting coal from North Korea. On Wednesday, the Chinese state-run newspaper Global Times carried an editorial that said public opinion supported the government toughening its sanctions on North Korea. The Global Times wrote that if North Korea conducted another nuclear test, Beijing's reaction would be unprecedented, and it was likely to vote in support of further sanctions in the Security Council. "If Pyongyang makes a big mistake, it may be very difficult to have opportunity for carrying out strategic correction," the editorial said. A veteran Beijing military commentator, Song Xiaojun, said he didn't expect Mr Trump to attack North Korea and said the tweets were "showing off". Mr Song said the rhetoric from the White House was designed to pressure China on trade and boost the prospects of a friendly South Korean presidential candidate in next month's election.

Mr Cai said South Korea and Japan would be unlikely to support a unilateral attack by the US: "Syria poses no threat to US or its allies at all. But North Korea has strong counter-strike capability. Although so far its nuclear missiles can't pose a direct threat to America, they are enough to strike America's allies in the region, South Korea and Japan," he said. According to the CCTV report of the call, Mr Xi stressed he was glad to talk on the phone, and reminded Mr Trump of the fruitful summit the two leaders had held recently at Mar-a-Lago, which had been evaluated positively by the international community. He said the two leaders had agreed to communicate and coordinate on major regional and international issues, and hoped the two countries would work together in promoting world peace and development. According to CCTV, Mr Trump had agreed on the importance of both leaders maintaining close contact, and they should work together to explore "pragmatic cooperation". Loading

On Syria, Mr Xi said it was unacceptable for any kind of chemical weapons to be used, and he hoped the UN Security Council could send out a unanimous message to solve the Syrian crisis. - with Sanghee Liu