Story highlights Xi Jinping and Moon Jae-in spoke for 40 minutes, according to South Korean officials

The two leaders discussed THAAD and the nuclear threat in the "first" call of its kind

(CNN) The election of South Korea's new president, Moon Jae-in, has given fresh hope of a thawing in relations with China, which have recently been strained due to the deployment of a controversial missile defence system in South Korea.

Chinese leader Xi Jinping called Moon Thursday to congratulate him for his electoral victory. During the 40-minute call, Xi stressed the importance of working together to achieve the common goal of denuclearizing the Korean peninsula - an aim dependent on resolving the thorny THAAD missile defence system issue.

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Tong Zhao, an associate fellow at the Carnegie Tsinghua Center for Global Policy, said while the two nations share a similar agenda, the THAAD issue is the number one problem between them.

Zhao said though the tone of the call showed progress, there were no real specifics at play and there's still a lot of uncertainty regarding how the two nations will move past the issue.

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