The United States has formally agreed on South Korea's plan to send Rep. Lee Soo-hyuck of the ruling Democratic Party as its new ambassador, Cheong Wa Dae confirmed Thursday.

Seoul recently received the diplomatic consent, known as "agrement," from Washington over the pick of the diplomat-turned-lawmaker, according to Cheong Wa Dae's deputy spokesperson Han Jung-woo.

President Moon Jae-in will soon appoint Lee so that he can assume the post, he said.

The consent came about two months after Lee was selected for the post.

Critics claimed the procedure took longer than usual because of Washington's displeasure with Seoul's recent decision to end an information-sharing deal with Japan. Seoul's foreign ministry dismissed the speculation, saying it's not far from the customary practice.

Lee, 70, served as South Korea's first chief nuclear negotiator for the six-party talks involving the two Koreas, the US, China, Japan and Russia, when it was launched in 2003, with the goal of resolving the North Korean nuclear issue.

The retired career diplomat also served as ambassador to Yugoslavia in 2002 and Germany in 2005, before entering politics in 2016, when Moon, the then opposition party chief, picked him to spearhead his party's subcommittee in charge of peninsula and inter-Korean affairs.

He won his parliamentary proportional representation seat in 2017. (Yonhap)