South Korean prosecutors are to question President Park Guen-hye as part of a probe into the political scandal swamping her tenure.
Her presidency has been rocked by the suspicion that she let a longtime confidante manipulate power from behind the scenes.
In a televised apology last week the president said she would accept a direct investigation into her actions.
It will be the first time a sitting president has been questioned by prosecutors.
The prosecution office also said the chairman of Hyundai Motor Company has been questioned over whether Park or anyone involved in the influence-peddling scandal put improper pressure on corporate bosses to raise funds for charitable foundations at the centre of the case.
On Saturday up to one million people took to the streets of Seoul to call for her resignation.