US Defense Secretary Ashton Carter and his South Korean counterpart vowed zero tolerance Monday “in the face of any North Korean provocations” and agreed to strengthen combined defenses against threats posed by Pyongyang.

US Defense Secretary Ashton Carter and his South Korean counterpart vowed zero tolerance Monday “in the face of any North Korean provocations” and agreed to strengthen combined defenses against 'threats' posed by Pyongyang.

Carter met with Han Min-Koo in Seoul during an annual security meeting for the two allies to assess their ongoing military cooperation.

Carter told reporters that the two officials "spoke candidly" about nuclear weapons, ballistic missiles, cyber, and conventional military threats from North Korea, which they described as a risk to peace and security well beyond the Korean peninsula.

"The minister and the secretary reaffirmed that any North Korean aggression or military provocation is not to be tolerated," according to a joint statement released after their talks.

They specifically voiced "grave concern" over strong hints from North Korea that it is prepping a long-range rocket launch in violation of US resolutions.

In a widely expected move, the defense chiefs signed an important agreement that defines conditions for a transfer of control of the South Korean military from the United States to Seoul in a time of war.

South Korea had been scheduled to take wartime control, known as OPCON, by the end of next year, but now the transfer is based on conditions being met and not a particular timeline.