Yoon Seok-youl, the leading opposition presidential contender, said Wednesday he will demand the United States redeploy its tactical nuclear weapons here and have nuclear sharing with South Korea if national security is threatened by North Korea's nukes and missiles.

Unveiling 11 election pledges on diplomacy and security issues, former Prosecutor-General Yoon said he will make efforts to strengthen the Seoul-Washington alliance to deter the North's evolving nuclear and missile capabilities.

Yoon of the main opposition People Power Party said he plans to seek consultation with the US over the process to bring in US nuclear strategic assets, such as intercontinental ballistic missiles, when emergency situations occur on the Korean Peninsula.

He stressed that despite the allies' efforts to strengthen extended deterrence, if national security is threatened by Pyongyang's nuclear weapons and missiles, he will request the redeployment of US tactical nukes and nuclear sharing.

The US introduced tactical nuclear weapons to South Korea in the late 1950s and then withdrew them in the early 1990s following a disarmament deal with the then Soviet Union, as well as the then South Korean government's efforts to promote reconciliation with the North.

But Yoon said his plan does not mean South Korea's nuclear armament, noting that he will prioritize diplomacy in resolving the North's nuclear issue.

Yoon also said he plans to set up a liaison office involving the two Koreas and the US at the border truce village of Panmunjom in a bid to run a trilateral dialogue channel on a permanent basis.

He added he will seek to operate economic cooperation projects with North Korea if there is progress toward the North's denuclearization. (Yonhap)