South Korean President Park Geun-hye will be questioned over allegations of political corruption in a scandal that has engulfed her presidency.
According to officials, this will be the first time a sitting president has been questioned by prosecutors.
Park Geun-hye is accused of allowing her friend Choi Soon-sil to manipulate power from behind the scenes.
Hundreds of thousands rallied on November 12 to demand her resignation.
South Korean news agency Yonhap quoted officials as saying Park Geun-hye’s questioning should take place no later than November 16.
Prosecutors have also questioned top executives at Samsung, Hyundai and Korean Air.
Lee Jae-Yong, vice chairman of Samsung Electronics, was questioned over whether Park Geun-hye pressured the company into donating millions to foundations controlled by her friend Choi Soon-sil.
Choi Soon-sil is accused of trying to extort huge sums of money from South Korean companies and is under arrest on charges of fraud and abuse of power.
She is suspected of using her friendship with President Park Geun-hye to solicit business donations for a non-profit fund she controlled.
Park Geun-hye, whose approval ratings have plummeted to 5% because of the scandal, has said she is “heartbroken”.
On November 12, organizers said some one million people encircled the presidential compound in the South Korean capital of Seoul, in the largest anti-government rally the country has seen.
It was the latest in weeks of demonstrations against President Park Geun-hye.
On November 13, the presidential office said Park Geun-hye was “earnestly considering ways to normalize state affairs” and that she had “heard the voices of the people at the rally”.
South Korea’s constitution does not allow a sitting president to be prosecuted, but investigations are permissible.
Park Geun-hye has 15 months left in her term. If she steps down elections must be held within 60 days.