Stephen Biegun, a U.S. special envoy to the Democratic People's Republic of Korea (DPRK) said on Friday that Washington was ready to hold constructive talks with Pyongyang to follow through on a denuclearization agreement reached by the two countries last year, Republic of Korea's (ROK) foreign ministry said. 

Biegun told his ROK counterpart Lee Do-hoon that Washington wanted to make "simultaneous, parallel" progress on the agreement reached by U.S. President Donald Trump and DPRK leader Kim Jong Un in their historic summit last year in Singapore, the ministry said in a statement. 

Both sides agreed to establish new relations and work toward denuclearization of the Korean Peninsula. 

But negotiations have stalled since a second summit in Vietnam in February collapsed as both sides failed to taper differences between U.S. calls for denuclearization and DPRK demands for sanctions partially relief. 

The envoys met ahead of Trump's visit to ROK this weekend, during which Trump and ROK President Moon Jae-in are expected to discuss ways to kick-start the stalled dialogue with Pyongyang. 

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"Biegun said the upcoming summit would provide a crucial chance to foster peace and prosperity of the Korean Peninsula," the ROK ministry said. 

Moon has said Washington was in behind-the-scenes talks with Pyongyang over a possible third summit and had proposed a fresh round of talks. But the DPRK said on Thursday that the U.S. had become "more and more desperate in its hostile acts" even as it spoke of dialogue.