US President Donald Trump has referred to the leader of North Korea Kim Jong-un as a "rocket man".
FILE - In this September 15, 2017 file photo, President Donald Trump waves as he walks from the Oval Office of the White House in Washington to Marine One for the short trip to Andrews Air Force Base, Md.
Recently, North Korea conducted a missile test that was capable of reaching Guam which falls in the U.S. as it flew 2,300 miles.
McMaster says Trump, much like previous presidents, will push a message of reform, calling for more transparency and accountability at the United Nations.
Trump condemned Friday's test-launch of what North Korea claimed was an intermediate-range Hwasong-12, saying Kim's leadership "has once again shown its utter contempt for its neighbors and for the entire world community".
"For those ... who have been commenting on a lack of a military option, there is a military option", he said, adding that it would not be the Trump administration's preferred choice.
Briefing reporters ahead of the annual United Nations meeting, Haley and H.R. McMaster - the White House national security adviser - took a tough line on North Korea, warning that a military option to deal with its nuclear threats was available.
"The two leaders agreed to strengthen cooperation, and exert stronger and practical sanctions on North Korea so that it realizes provocative actions leads to further diplomatic isolation and economic pressure", Blue House spokesman Park Soo-hyun said in a televised briefing. Haley and Trump's national security adviser, H.R. McMaster, outlined the president's goals for next week's United Nations summit.
"Our final goal is to establish the equilibrium of real force with the USA and make the US rulers dare not talk about military option for the DPRK", leader Kim Jong-un reportedly said.
"We've been kicking the can down the road, and we're out of road", McMaster told reporters, referring to Pyongyang's repeated missile tests in defiance of global pressure.
"As Kim Jong-Un's most recent launch demonstrates, this is one of the world's most urgent and unsafe security problems", he added.
McMaster called for "rigorous enforcement" by all United Nations member states of UN sanctions on North Korea, including the latest package that for the first time capped oil supply to the country, as a way of compelling it to alter its provocative behavior.
The ambassador said she has "no problem kicking it to Gen. Mattis", the U.S. Defense Secretary, because "I think he has plenty of options".
"I believe it will further North Korea's isolation - diplomatic and economic isolation - because more and more nations are realising there's simply no collaboration with the worldwide community". North Korea also has the world's largest standing army.