The potential of North Korea utilizing a nuclear bomb was the topic of a simulated “table-top” exercise in which U.S. and South Korean officials took part, the Military announced on Thursday.

Nuclear-armed In 2017, North Korea launched an unprecedented number of missiles, including ICBMs, that could strike the U.S. mainland. In addition, it fired two missiles into the Pacific Ocean on Monday.

The North may be ready for its first nuclear test since 2017.

The 8th U.S.-South Korean deterrent strategy committee table-top exercise (DSC TTX) was the first since they decided to hold it yearly last year.

“With the DPRK’s recent aggressive nuclear strategy and developments in nuclear capabilities, the (table top) scenario focused on the prospect of the DPRK’s use of nuclear weapons,” the Military stated.

“The U.S. and South Korea delegations centered their conversation on Alliance deterrence to maintain peace and stability on the Korean Peninsula and potential options for reacting to DPRK nuclear weapons use,” the statement said, without elaborating.

Seoul’s defense ministry said the allies agreed to strengthen intelligence sharing, crisis consultation, coordinated planning, and extended deterrence in response to North Korean nuclear threats.

“The U.S. side reiterated that any use of nuclear weapons by North Korea against the United States or its allies and partners would be unacceptable and result in an end of its dictatorship,” the ministry stated.

After the Pentagon simulation on Wednesday, representatives from both nations visited Navy Submarine Station Kings Bay in Georgia.

The statement said the delegates addressed ways to use South Korea’s non-nuclear capabilities to prevent Pyongyang’s nuclear threats.

Since taking office in May, South Korean President Yoon Suk-year has sought to boost trust in extended American deterrence—the military power, notably nuclear forces, to deter assaults on its allies—as Pyongyang seeks to guarantee its ability to strike anyplace in the U.S.

If North Korea conducts a nuclear test, Yoon threatened an unprecedented coordinated reaction with allies in November.