There have been allegations that Choi recommended Yoo to the president to gain economic profits through businesses in Myanmar.

Choi and Yoo are known to have had a face-to-face meeting in March 2016. 

"I still do not know who recommended me as ambassador," Yoo told reporters as he arrived at the probe team's office. "If somebody has recommended me to this post with an ulterior motive, I can tell you that the person has got the wrong person." 

He did not directly mention Choi and declined to comment when asked if he actually had the meeting in March.

"Upon appointment, I was told by the president that they were looking for somebody with experience in trade, instead of an authentic diplomat, so as to tap into the new market," Yoo added.  

It is the second time for an incumbent ambassador stationed abroad to be called in by investigators in relation to the scandal. 

South Korea's Ambassador to France Mo Chul-min returned to South Korea last month, following the investigation team's summons over suspicions the presidential office created a "blacklist" of cultural figures considered critical of the government. Mo served as a senior presidential secretary from 2013 to 2014. (Yonhap)