US President Donald Trump tweeted criticism of North Korea, saying the nation was “behaving badly” and blamed China for doing little to help, just a day before US State Secretary Rex Tillerson is due to arrive in Beijing. North Korea is behaving very badly. They have been "playing" the United States for years. China has done little to help! — Donald J. Trump (@realDonaldTrump) March 17, 2017 <!--//--><![CDATA[// ><!--\n\n\n//--><!]]> “North Korea is behaving very badly, they have been “playing” the United States for years. China has done little to help!” he said on his official Twitter account. Just earlier in Seoul, Tillerson declared an end of US “strategic patience” with North Korea and warned military action would be an option if security threats by Pyongyang escalated. “Certainly, we do not want things to get to a military conflict ... but obviously if North Korea takes actions that threaten the South Korean forces or our own forces, then that would be met with an appropriate response,” Tillerson told reporters. Speaking to the South China Morning Post privately, Chinese diplomats said they had long been cautious about Trump and how much Tillerson’s visit could help with the security situation in East Asia. “We are still scratching our heads to work out how to deal with Trump in the wake of the roller-coaster ride of China-US relations since he got elected,” one diplomat said earlier. US Secretary of State Rex Tillerson says military action against North Korea an ‘option on the table’ Instead of creating “a friendly environment” prior to his landmark visit to China on Saturday as was hoped, Tillerson had criticised China for exerting economic pressure on South Korea over the installation of a US missile defence shield known as the Terminal High Altitude Area Defence system (THAAD). “While we acknowledge China’s opposition, its economic retaliation against South Korea is inappropriate and troubling,” Tillerson said. “We ask China to refrain from such actions. Instead we urge China to address the threat that makes THAAD necessary – that being the escalating threat from North Korea.” Xinhua, in response, issued a statement by the Chinese foreign ministry saying Beijing’s opposition to the missile shield was justified.