South Korea's President Moon Jae-in lobbied US leaders on Thursday to back his policy of engagement with North Korea in his first overseas trip since a landslide election victory in May. Moon met the US Congress and President Donald Trump on Thursday.
Talks between the two leaders will continue into Friday. Trump is expected to press Moon to solve trade differences over cars and steel during meetings which will focus on the nuclear threat from North Korea.
The Trump administration has been trying to isolate North Korea following a series of missile tests as Trump has made the North a top security priority, pursuing a policy of "maximum pressure."
Trump’s strategy includes persuading China – Pyongyang's main ally – to help bring North Korea's leader Kim Jong-un in line.
"Most people have believed that the path to get to North Korea goes through China," Council on Foreign Relations Director of the Program on US- Korea Policy Scott Snyder said.
"The Chinese may also think that. One way of motivating the Chinese to do more is to show them there is an alternative path."
TRT World’s Sally Ayhan brings the latest on US and South Korea's ties.
Moon, seeking to calm tensions, said on Wednesday that Seoul and Washington should offer concessions to Pyongyang if it complies with their demands, according to multiple South Korean reports.
"Without rewarding North Korea for its bad actions, South Korea and the United States should closely consult what they may give the North in return for a nuclear freeze," he said.
"A nuclear freeze is a gate to dialogue and the exit of the dialogue is complete nuclear dismantlement," Moon said.
Washington and Seoul "share precisely the same goal, which is the complete dismantlement of North Korea's nuclear and missile programme," a senior US administration official said. Trump seeks to heap economic and diplomatic pressure on Pyongyang "in order to change their calculus," the official added.
Also expected to be high on the Moon-Trump agenda is a controversial US missile defence system that has been installed in South Korea to guard against missile threats from the North.
Parts of the Terminal High-Altitude Area Defense (THAAD) system are already in place, much to the dismay of South Koreans who see it as a US overreach.
Moon suspended further deployment following a furious campaign of economic sanctions and diplomatic protests by Beijing.
Washington has more than 28,000 troops in South Korea to defend it from its communist neighbour.