Prosecutor General Shim Woo-jung arrives for work at the Supreme Prosecutors Office in Seoul on Thursday. (Yonhap)

The main opposition Democratic Party said Friday it will take steps to impeach Prosecutor General Shim Woo-jung over the prosecution's decision not to indict first lady Kim Keon Hee over her alleged involvement in a stock manipulation scheme.

"The (DP) leadership discussed the issue of impeaching the prosecutor general and concluded to go ahead with it," Jo Seoung-lae, a senior DP spokesperson, told reporters after a Supreme Council meeting. "The steps and timing of the impeachment will be discussed with the floor leadership."

The Seoul Central District Prosecutors Office announced the nonindictment Thursday, four and 1/2 years after the investigation began into allegations that Kim's stock trading accounts were used in a massive stock price manipulation scheme involving Deutsch Motors Inc., a BMW dealer, between 2009-2012.

Prosecutors concluded that she did not know her accounts were used for manipulation. (Yonhap)