"We are prepared to engage as soon as we hear from our counterparts in North Korea (DPRK)," said Stephen Biegun, Xinhua news agency reported.
Biegun made the remark after a meeting in Seoul with Lee Do-hoon, South Korea's special representative for Korean Peninsula peace and security affairs, according to local media reports.
The US envoy said he will be "fully committed to this important mission" as US President Donald Trump gave him the assignment to resume working-level talks with the DPRK following the US president's meeting with top DPRK leader Kim Jong Un in late June.
Kim and Trump held an impromptu meeting at the inter-Korean border village of Panmunjom on June 30, agreeing to restart a working-level dialogue to implement the Singapore agreement, signed by the two leaders during their first-ever summit in Singapore in June last year.
The two leaders met again in late February in the Vietnamese capital of Hanoi, but the second DPRK-US summit ended without any agreement. Under the Singapore deal, Kim and Trump agreed to the complete denuclearisation of and the peace settlement in the peninsula.
Lee, the South Korean nuclear envoy, told reporters that he had a productive dialogue with Biegun as they discussed how to rapidly resume talks between Pyongyang and Washington and make substantive progress in the negotiation for the denuclearisation.
He noted that Biegun visited Seoul at a proper time when efforts were necessary to restart the DPRK-US working-level talks.
Biegun arrived here from Japan Tuesday evening, right after the end of the South Korea-US joint military exercises.
The DPRK criticised the South Korea-US joint military drills as a rehearsal for northward invasion, test-firing short-range projectiles into the East Sea before and during the drills to protest against it.
( With inputs from IANS )