At a joint appearance with South Korean President Moon, US President Donald Trump said North Korea's nuclear and ballistic missile programs required a "determined response."
US President Donald Trump called for a determined response to North Korea after talks with South Korean President Moon Jae-in on Friday at which he emphasised the importance of their alliance but took aim at Seoul over trade and defence spending.
At a joint appearance with Moon after two days of talks, Trump reiterated that an era of "strategic patience" over North Korea's nuclear and ballistic missile programmes had ended.
"Together we are facing the threat of the reckless and brutal regime in North Korea. The nuclear and ballistic missile programmes of that regime required a determined response," Trump said while standing alongside Moon in the White House Rose Garden.
"We're working closely with South Korea and Japan, as well as partners around the world, on a range of diplomatic, security and economic measures to protect our allies and our own citizens from this menace known as North Korea," he said.
TRT World's Sally Ayhan has more from Washington.
Moon said he and Trump had placed top priority on the North Korean issue.
"President Trump and I agreed that only strong security can bring about genuine peace," Moon said. "The threat and provocation of the North will be met with a stern response."
"Our two leaders will employ both sanctions and dialogue in a phased and comprehensive approach" in an effort to resolve the North Korean nuclear issue, Moon said.
While South Korea is a long-standing ally of the US, Trump has spoken harshly about US trade imbalances and threatened to tear up a five-year-old trade agreement reached with South Korea by his predecessor, Barack Obama.
He said on Friday that the US was renegotiating what he characterised as a "rough" trade deal with South Korea.
"We will do more to remove barriers to reciprocal trade and market access," Trump said, adding that the two leaders had talked about the thorny trade areas of steel and autos.
"I am encouraged by President Moon's assurances that he will work to create a level playing field so that American workers and businesses, and especially automakers, can have a fair shake at dealing with South Korea," he said.
Trump also stressed the need to ensure equitable sharing of costs for defence between the United States and South Korea, returning to a theme he had raised during his campaign.
Moon said he had had "candid and lengthy" talks and that the meetings had been a great opportunity "to further trust and friendship" with Trump.
On Wednesday, Moon said that unfair trade practises would be eradicated and factors that limited competition, such as barriers to market entry and price regulations, would be re-evaluated under his administration.
The US goods trade deficit with South Korea has more than doubled since the KORUS pact took effect in 2012, from $13.2 billion in 2011 to $27.7 billion in 2016. It was forecast to boost US exports by $10 billion a year, but they were $3 billion lower in 2016 than in 2011.
The full joint press statement can be watched below.