As the rhetoric continued to escalate Opposition Leader Bill Shorten - who is in South Korea to discuss the security crisis - called for calm. North Koreans gather at Kim Il Sung Square to attend a mass rally against America on Saturday. Credit:AP "We need cool, sober, heads working for de-escalation, not actions that further inflame an already volatile situation," he said. Mr Shorten and his foreign affairs spokeswoman, Penny Wong, will meet with South Korean Prime Minister Lee Nak-yeon and former Secretary-General of the United Nations Ban Ki-Moon for talks on Monday. On Tuesday they will meet with the Commander of US Forces in Korea, General Vincent K. Brooks, and travel to the border's de-militarised zone.

"This is a critical time for a part of the world that is critical to Australia's security and economic success," Mr Shorten said. "We must work to turn this rogue state away from further aggression and help restore stability and security to the region." North Korean Foreign Minister Ri Yong-Ho called US President Donald Trump "a mentally deranged person full of megalomania". Credit:AP Trump's latest tweet capped off a week of escalating rhetoric between Washington and Pyongyang, with Trump and Kim Jong-un trading insults. Trump called the North Korean leader a "madman" on Friday, a day after Kim dubbed him a "mentally deranged US dotard." On Saturday, the mudslinging continued with Ri calling Trump "a mentally deranged person full of megalomania and complacency" who is trying to turn the United Nations into a "gangsters' nest". Ri retorted that Trump himself was on a "suicide mission" after the US President said Kim was on such a mission. He said sanctions would have no effect on Pyongyang's resolve to develop its nuclear weapons, with the ultimate goal being "balance of power with the US".

A huge crowd gathered on Saturday in Pyongyang's Kim Il Sung Square, named for the current leader's grandfather and founder of North Korea. They listened to speeches from senior officials excoriating the US and its President. A parade of marchers carried signs with slogans such as "decisive revenge" and "death to the American imperialists". They shouted phrases such as "total destruction", according to the Korean Central News Agency, the state news service. The crowd included workers, officials and students, KCNA said. The rally capped two days of response to Trump's combative speech at the United Nations on Thursday, where the US President announced new sanctions that he said would allow targeting of companies and institutions that finance and facilitate trade with North Korea. Earlier this month the UN Security Council unanimously adopted its ninth round of sanctions on Pyongyang to counter its nuclear and ballistic missiles programs.

The US bombers' flight was the farthest north of the demilitarised zone separating North and South Korea that any US fighter jet or bomber has flown in the 21st century, the Pentagon said. "This mission is a demonstration of US resolve and a clear message that the President has many military options to defeat any threat," said Pentagon spokeswoman Dana White. "We are prepared to use the full range of military capabilities to defend the US homeland and our allies." North Korea has launched dozens of missiles this year, several flying over Japan, as it accelerates its program aimed at enabling it to target the United States with a nuclear-tipped missile. Pyongyang conducted its sixth and largest nuclear test on September 3 and has threatened to test a hydrogen bomb over the Pacific.

The Pentagon said the B-1B bombers came from Guam and the US. Air Force F-15C Eagle fighter escorts came from Okinawa, Japan. It said the operation showed the seriousness with which it took North Korea's "reckless behavior." The patrols came after officials and experts said a small earthquake near North Korea's nuclear test site on Saturday was probably not man-made, easing fears Pyongyang had exploded another nuclear bomb just weeks after its last one. China's Earthquake Administration said the quake was not a nuclear explosion and had the characteristics of a natural tremor. The CTBTO, or Comprehensive Test-Ban Treaty Organization, which monitors nuclear tests, and officials of the South Korean meteorological agency also said they believed it was a natural quake. The earthquake, which South Korea's Meteorological Agency put at magnitude 3.0, was detected 49 km from Kilju in North Hamgyong Province, where North Korea's known Punggye-ri nuclear site is located, the official said.

All of North Korea's six nuclear tests registered as earthquakes of magnitude 4.3 or above. The last test registered as a 6.3 magnitude quake. Tensions have continued to rise around the Korean Peninsula since Pyongyang carried out its sixth nuclear test, prompting a new round of U.N. sanctions. Trump told the United Nations on Tuesday the United States would "totally destroy" North Korea if it threatened the United States or its allies. North Korea's nuclear tests to date have all been underground, and experts say an atmospheric test, which would be the first since one by China in 1980, would be proof of the success of its weapons program. The United States and South Korea are technically still at war with North Korea because the 1950-53 Korean conflict ended with a truce and not a peace treaty.

Loading The North accuses the United States, which has 28,500 troops in South Korea, of planning to invade and regularly threatens to destroy it and its Asian allies. Reuters