Donald Trump stepped up his threats against North Korea on Thursday, declaring that he may not have been “tough enough” in his earlier warning to Pyongyang that the US would rain “fire and fury like the world has never seen” if the country did not abandon its nuclear ambitions.

“They’ve been doing this to our country for a long time, for many years, and it’s about time that somebody stuck up for the people of this country and for the people of other countries,” the president told reporters. “If anything, maybe that statement wasn’t tough enough.”

In the wake of the remarks, the 10-year Treasury yield dipped 4 basis points to a two-month low of 2.2 per cent as investors sought out the safety of US government debt. The S&P 500 ended down 1.45 per cent at a one-month low of 2,438.