The ruling Democratic Party on Sunday welcomed North Korea's announcement of a detailed plan to dismantle its nuclear test site as a first step toward complete denuclearization, while the main opposition Liberty Korea Party downplayed it as nothing new.

The North's foreign ministry announced Saturday night that it will dismantle its Punggye-ri nuclear test site between May 23 and 25, and will invite journalists from South Korea, China, Russia, the United States and Britain to cover the dismantling on-site.

"We welcome the decision to shut down the Punggye-ri nuclear test site, which is the first step toward complete denuclearization," Rep. Baek Hye-ryun, a spokesperson of the ruling party, said in a statement. "This will serve as an opportunity to promote the trust of the international community, including the United States, (in North Korea) ahead of the US-North Korea summit."