South Korean President Moon Jae-in and Chinese President Xi Jinping vowed to closely work together to declare an end to the Korean War and sign a peace treaty with North Korea in a phone call, Cheong Wa Dae said Friday.

Seoul’s presidential office said the two leaders discussed the outcome of the inter-Korean summit held on April 27 in a phone conversation which lasted from 5 p.m. to 5:35 p.m., a week after Moon held a historic summit with North Korean leader Kim Jong-un at the truce village of Panmunjeom.

“President Moon stressed that President Xi’s continued interest and support, as well as the Chinese government’s active contribution, are important in completely denuclearizing the Korean Peninsula and establishing permanent peace,” the presidential office said in a press release.

In the Panmunjeom Declaration, Moon and Kim agreed to push for complete denuclearization of the Korean Peninsula and replace an armistice, which left the two Koreas technically at war, with a peace treaty.

Xi welcomed the inter-Korean agreement, promising his full support, according to Cheong Wa Dae.

“President Xi congratulated the successful outcome of the South-North Korea summit and the Panmunjeom Declaration, and said President Moon’s efforts to bring about a positive change to conditions surrounding the Korean Peninsula had been critical of such an outcome,” it said.

Xi told Moon that Kim had reaffirmed his willingness to denuclearize, end hostilities on the Korean Peninsula and improve inter-Korean ties during his meeting with Chinese Foreign Minister Wang Yi earlier this week in Pyongyang, according to the presidential office.

“He said Chairman Kim again confirmed his willingness to shut down the North’s Punggye-ri nuclear test site and end the history of hostility on the Korean Peninsula through a declaration of an end to the Korean War,” it said

Moon and Xi “also agreed the two countries will closely communicate and actively cooperate in the process of replacing the Korean armistice with a peace treaty,” it added.

The phone call came as China appears to be struggling to retain an influence in the process of denuclearization and building a peace regime on the peninsula.

The presidential office said Wednesday that China could be left out of the process of declaring an end to the Korean War, but added its role was essential in signing a peace treaty with the North.

In the joint declaration, Moon and Kim said they would seek to hold three-way talks among the two Koreas and the US, or four-way talks involving China. The US and China are both signatories to the armistice.

The Chinese foreign minister visited North Korea from Wednesday to Thursday at the invitation of his North Korean counterpart Ri Yong-ho. It marked the first visit to North Korea by a Chinese foreign minister in 11 years.

Wang met North Korean leader Kim Jong-un on Thursday. He met Ri on Wednesday to discuss ways to improve the two countries’ ties and the situation on the Korean Peninsula, the North’s state-run Korean Central News Agency said.

China, North Korea’s traditional ally and biggest trading partner, has tried to improve its frayed relations with Pyongyang in recent months, in a move to dismiss concerns that it is being left out of critical decisions on the Korean Peninsula and losing its influence over the North Korean regime -- a key point of leverage over the US.

Beijing’s relations with Pyongyang have been strained due to its backing of international sanctions against the reclusive regime over the North’s nuclear weapons programs.

Moon is set to hold a trilateral meeting with Japanese Prime Minister Shinzo Abe and Chinese Premier Li Keqiang on the outcome of the inter-Korean summit on May 9.

By Ock Hyun-ju (laeticia.ock@heraldcorp.com)