WASHINGTON-- South Korea and the US held simulation drills in Washington this week to enhance nuclear deterrence cooperation, both sides said Friday, as the allies are stepping up security coordination to counter evolving North Korean threats.

Seoul and Washington held the first table top simulation of the Nuclear Consultative Group, the allies' key nuclear deterrence dialogue body, on Thursday and Friday, Seoul's defense ministry and the Pentagon said in a joint statement.

The TTS drills involved officials from the two countries' national security, military, diplomatic and intelligence authorities, it said.

"The simulation greatly contributes to the work of NCG, especially by strengthening the alliance's approach to cooperative decision-making about nuclear deterrence and planning for potential nuclear contingencies on the Korean Peninsula," they said in the release.

During the TTS program, the US reaffirmed America's "ironclad" extended deterrence commitment to South Korea, according to the release. Extended deterrence refers to the U.S.' pledge to use the full range of its military capabilities, including nuclear, to defend its ally.

TTS followed the latest session of the Extended Deterrence Strategy and Consultation Group, another bilateral deterrence dialogue body, in Washington on Wednesday.

The allies' deterrence efforts came as Pyongyang has been doubling down on its nuclear and missile programs in the midst of its deepening military cooperation with Moscow, while meaningful diplomacy to curb the North's nuclear threats has stalled.

Concerns have also lingered that the recalcitrant regime could engage in provocative acts before the U.S. presidential election in November.

Seoul and Washington launched the NCG in July last year in line with the Washington Declaration that President Yoon Suk Yeol and U.S. President Joe Biden issued at their summit in April last year to strengthen the credibility of America's extended deterrence commitment.