Moon Jae-in will reportedly visit the White House next month for a summit with President Donald Trump amid worries over North Korea's progress in building a nuclear and missile arsenal.
More cyberattacks could be in the pipeline after the global havoc caused by the Wannacry ransomware.
North Korea on Monday boasted of a successful weekend launch of a new type of "medium long-range" ballistic rocket that can carry a heavy nuclear warhead.
U.S. President Donald Trump called for tougher sanctions against North Korea after it test fired a ballistic missile Sunday in an apparent attempt to test the South's new liberal president and the U.S.
North Korea on Sunday test-launched a ballistic missile that flew about 700 kilometers (435 miles), South Korea's military said, a possible response to the election four days ago of a new South Korean president and as U.S., Japanese and European militaries gather for war games in the Pacific.
South Korea's new president Moon Jae-In spoke to the leaders of China and Japan Thursday, hours after a telephone call with his U.S. counterpart Donald Trump, officials said, as he began shaping his approach to the nuclear-armed North.
Pyongyang will seek the extradition of anyone involved in what it says was a CIA-backed plot to kill leader Kim Jung Un last month with a biochemical poison, a top North Korean foreign ministry official said Thursday.
New South Korean President Moon Jae-in said as he took office Wednesday that he is open to visiting rival North Korea under the right conditions to talk about its aggressive pursuit of nuclear-tipped missiles.
Left-leaning former human rights lawyer Moon Jae-in won South Korea's presidential election by a landslide, an exit poll predicted when voting closed Tuesday.
Exit polls in South Korea forecast that liberal candidate Moon Jae-in will win an election Tuesday to succeed ousted President Park Geun-hye.