Imposing sanctions will be the most effective way to rein in North Korea's nuclear ambitions as decades of inter-Korean talks failed to induce any positive changes in the reclusive country, South Korea's unification ministry said Wednesday. 

South Korea reiterated its firm stance toward the North in response to North Korean Foreign Minister Ri Yong-ho's remarks made a day earlier at a press meeting held on the sidelines of the ASEAN Regional Forum in the Laotian capital.

At the meeting Ri said, "We have made various proposals aimed at resolving inter-Korean relations through conversation and negotiations but all of them have been rejected. All of them. We don't think at this point that the South is prepared to engage in talks."

Unification Ministry spokeswoman Park Soo-jin fired back, saying there should first be changes in the North's policy of seeking to become a nuclear power state if it wants any meaningful dialogue with the South.

"Sanctions and dialogue are compatible options as long as they can induce North Korea to abandon its nuclear programs. But decades of South Korean aid and efforts for development of inter-Korean relations have been met by North Korea's nuclear and missile tests," said Park.

"Now, it's time to fundamentally change North Korea's calculus through strong sanctions," she said.

The latest remarks come as Seoul has made clear that Pyongyang must confirm its commitment to giving up its nuclear program before any dialogue takes place.

Despite warnings by the international community, the North conducted nuclear tests in 2006, 2009 and 2013, with the last one taking place in January of this year.

Minister Ri also criticized Seoul's recent decision to deploy an advanced U.S. anti-missile system in South Korea.

But the move is "part of our self-rescue measures to better deal with repetitive nuclear and missile threats from the North," the spokeswoman said.

On July 19, North Korea test-fired three ballistic missiles in protest against the planned deployment of the Terminal High-Altitude Area Defense system in Seongju, 296 kilometers south of Seoul, by the end of 2017. (Yonhap)