WASHINGTON - US President Donald Trump said on Friday North Korea is "behaving very badly" and China has done little to help, hours after Secretary of State Rex Tillerson said a US policy of strategic patience with North Korea had ended."North Korea is behaving very badly. They have been 'playing' the United States for years. China has done little to help!" Trump said in a message on Twitter.Tillerson, who is currently in Seoul, is due to visit China on Saturday and Sunday to meet Chinese President Xi Jinping.