U.S. House of Representatives Speaker Nancy Pelosi and her South Korean counterpart vowed on Thursday to support efforts to maintain a strong deterrence against North Korea and achieve its denuclearization.

A joint statement was issued after Pelosi met South Korea's National Assembly Speaker Kim Jin-pyo in Seoul, in which they expressed concerns over the North's evolving nuclear and missile threats.

"Both sides expressed concerns about the dire situation of North Korea's growing threat," the statement said.