Jim Mattis, the US defence secretary, on Monday urged senior officers to be ready with military options for Donald Trump to deal with North Korea if diplomacy falls short, days after the President reprimanded Pentagon officials for not providing plans fast enough.

He delivered his remarks at the annual Association of the United States Army meeting in Washington as the Trump administration continues to signal its frustration at being unable to rein in Pyongyang with diplomatic measures.

“It is right now a diplomatically led, economic sanctions-buttressed effort to try to turn North Korea off of this path,” Mr Mattis said, according to The Hill.

“What does the future hold? Neither you nor I can say, so there is one thing the US Army can do. And that is you have to be ready to ensure that we have military options that our president can deploy if needed.”

Other nations have issued calls for restraint, amid fears that any US action could prompt deadly reprisals by Kim Jong-un’s unpredictable regime.