South Korea's Presidential Chief of Staff Im Jong-seok has met with a top U.S. nuclear envoy to discuss cooperation between the two allies to achieve the denuclearization of the Korean Peninsula. 

The presidential office said in a statement that Im met with U.S. Special Representative for North Korea Stephen Biegun at the top office on Monday afternoon.

In the rare meeting, President Moon Jae-in's chief secretary reportedly asked Biegun to lead U.S.-North Korea talks successfully, while the U.S. envoy called for Seoul's support in the process.

The top office said the two officials had in-depth discussions regarding the denuclearization of the Korean Peninsula and developments in the planned second U.S.-North Korea summit. 

The presidential office said that Washington asked Seoul to arrange the envoy's meeting with Moon's chief secretary. 

Biegun will reportedly meet with Moon's national security adviser Chung Eui-yong on Tuesday afternoon at the presidential office.