SEOUL, May 18 (UPI) -- John Kerry said Monday he's waiting for North Korea to get "serious" about the issue of its nuclear program – and discussed the U.S. missile defense system THAAD with U.S. military personnel in Seoul.
The U.S. Secretary of State told reporters in Seoul that stricter sanctions would be placed on North Korea if Pyongyang does not fulfill its commitment to denuclearize, Bloomberg reported.
In 2005, member nations of the six-party talks concurred to commit to the denuclearization of the Korean peninsula – an agreement that North Korea has since violated.
"We are more determined than ever to find a way to convince Kim Jong Un and North Korea that all they are doing now is isolating themselves further and creating greater risks for the region and for their country," said Kerry, referring to Pyongyang's ballistic missile development and belligerent stance toward Seoul and Washington.
In early May, North Korea's KCNA announced the launch of its first SLBM, or submarine-launched ballistic missiles, and South Korea issued a warning after the test.
Kim Jong Un reportedly said the missile was a "world-level strategic weapon capable of striking and wiping out in any waters the hostile forces infringing upon [North Korea's] sovereignty and dignity."
Kerry said the United States is waiting to offer North Korea an "improved bilateral relationship" when the reclusive country shows a "genuine willingness to fulfill denuclearization obligations."
On the topic of high-profile executions inside North Korea, Kerry said recent events tie into "the behavior of Kim Jong Un," whose regime is "one of the most egregious examples of reckless disregard for human rights."
South Korean President Park Geun-hye's condemnation of Kim Jong Un on Friday was matched by retaliatory North Korea remarks, referring to the South Korean head of state as a "viper."
In his last stop on his scheduled visit to Seoul on Monday, Yonhap reported Kerry met with U.S. soldiers at Yongsan Garrison and said the North Korea threat is the reason why THAAD, or Terminal High Altitude Area Defense, has been raised with South Korea.
Yonhap reported Kerry did not broach the topic of THAAD at the press conference.
The missile defense system is opposed by Beijing and Moscow because of radar that extends for 621 miles.