The State Department made all-out efforts in 2011 to break a hold that a senator had put on the confirmation of then-nuclear envoy Sung Kim as ambassador to South Korea, newly released emails of former Secretary of State Hillary Clinton showed.

After serving as special envoy for the six-party talks on ending North Korea's nuclear program, Kim was nominated by President Barack Obama in June 2011 to be his top envoy in Seoul.

The nomination, which had widely been expected to be confirmed easily by the Senate, encountered an unexpected hurdle as a Republican senator from Arizona, Jon Kyl, put a hold on Kim's confirmation over U.S. policy on North Korea.

As efforts to persuade the senator to lift the hold produced no breakthrough, then-Deputy Assistant Secretary for Senate Affairs Miguel Rodriguez sent an SOS email on Oct. 6, 2011, asking a series of top department officials for help, according to the Clinton emails.

"Apologies for casting the net so broadly, but we're stuck, and I could use some advice and help," Rodriguez said in the email sent to then-Deputy Secretary William Burns, Under Secretary Wendy Sherman, Clinton's Chief of Staff Cheryl Mills, Assistant Secretary Kurt Campbell and others.

Rodriguez said that Kyl sent him a letter in mid-September regarding North Korea, and his team responded to the letter promptly. As the senator asked several follow-up questions, Rodriguez said he was trying to set up "a classified briefing to address all their questions."

What the senator was seeking through the questions included specificity regarding the required actions on the part of North Korea, including the standard by which the administration will judge the North's sincerity, the administration's definition of nuclear programs and the administration's plans regarding food aid, sanctions relief and energy assistance to the North, Rodriguez said.

Sherman sent a response, but it was unclear what her point was as some of the response was blacked out before being disclosed to the public. In subsequent emails, Rodriguez also said he asked Sens. John Kerry and John McCain to reach out to Kyl to "see what if anything they can work out."

After a week of such exchanges and efforts, the senator lifted the hold on Kim on Oct. 13. It was unclear in the Clinton emails what led the senator to do so, but the department is believed to have provided sufficient answers to his questions.

Kim served as ambassador to South Korea from November 2011 to October 2014. After returning to Washington, he has been serving as a special representative for North Korea policy, as well as a deputy assistant secretary for Korea and Japan. (Yonhap)