SEOUL (Reuters) - South Korea’s parliament on Thursday approved a bill to appoint a special prosecutor to investigate a favors scandal engulfing President Park Geun-hye, sharply raising political pressure on her amid calls for her to step down.

South Korean President Park Geun-hye delivers her speech during the inaugural session of the 20th National Assembly in Seoul, South Korea, June 13, 2016. REUTERS/Kim Hong-Ji

Park’s administration has been rocked by allegations that a friend, Choi Soon-sil, used her ties to the president to meddle in state affairs and wield improper influence, triggering calls for the president to be impeached or step down.

Legal scholars and political analysts believe Park is unlikely to resign and that impeachment by parliament is more likely. The special prosecutor will have up to 120 days to investigate the case and can bring charges.

The motion for a special prosecutor proposed by the main opposition Democratic Party passed by a vote of 196 in the 300-seat assembly, indicating some members of Park’s ruling Saenuri Party backed the bill.

“We would like to propose this bill to resolve the public suspicion by appointing and allowing a special prosecutor to thoroughly find the truth through a strict investigation into allegations that civilians including Choi Soon-sil meddled in state affairs,” the bill said.

Park is under intense pressure from an angry public to step down with hundreds of thousands marching in the capital on Saturday.

Prosecutors are separately investigating Choi, who is alleged to have used her ties to the president to interfere in state affairs and wield influence in the cultural and sports communities, a prosecutor has previously said.

Park’s lawyer, Yoo Yeong-ha, told reporters on Thursday that he would cooperate with prosecutors for her to be questioned next week, Yonhap news agency reported, which would make her the first sitting leader to be questioned in a criminal case.

Reuters could not immediately reach Yoo for comment.

Park came under criticism from opposition parties that she was trying to stall the probe. The prosecutors had said they would try to question Park this week.

Park said in her nationally televised apology earlier this month that she would be open to a special prosecutor’s investigation.