The top U.S. official for North Korea policy resigned last week, multiple sources said Tuesday, adding to uncertainty over Washington's diplomatic efforts to reengage with a recalcitrant Pyongyang. Jung Pak left the post as the U.S. senior official for North Korea and a process is under way to select her replacement, according to the sources. Pak, a scholar-turned-diplomat, took over the post for North Korea policy at the State Department after Sung Kim, a veteran diplomat, retired late last year. She also served as deputy assistant secretary of state for East Asia and Pacific affairs. In a press briefing later, Matthew Miller, the State Department's spokesperson, said that Daniel Kritenbrink, assistant secretary of state for East Asian and Pacific affairs, will oversee North Korea policy for the department, while confirming Pak's resignation. "First of all, yes, she has stepped down, and we do thank Dr. Pak for her tireless dedication and strong leadership on DPRK since assuming office in 2021," he said , referring to the North by its official name, the Democratic People's Republic of Korea. "We wish her well on future endeavors." Her departure came as the United States has repeatedly shown its desire to engage in diplomacy with the North -- an overture that has only been met with Pyongyang's dogged endeavor to advance its nuclear and ballistic missile programs. She has led a series of efforts to strengthen cooperation between South Korea and the United States, and among South Korea, the U.S. and Japan over North Korea-related issues. Pak previously served as a senior researcher at the Brookings Institution. She also worked at the Central Intelligence Agency. Source: Yonhap News Agency