Prosecutors were questioning Health Minister Cho Kyoo-hong on Thursday as part of a widening investigation into the botched martial law order by President Yoon Suk Yeol, officials said.

The special prosecution team handling the probe called Cho in for questioning over his alleged involvement in Yoon's martial law declaration, including his attendance at a Cabinet meeting where the martial law was believed to have been discussed.

Cho is the first known Cabinet member to be undergoing questioning in the probe.

Cho was among the 11 Cabinet officials, including Prime Minister Han Duck-soo, who were present at the meeting that took place minutes before Yoon declared the martial law decree last Tuesday night.

Yoon rescinded the order hours after the National Assembly voted to reject it.

Cho did not attend the Cabinet meeting held after the martial law was lifted.

Cho has told parliament that he did not agree to the martial law, but there were "limitations" in speaking out as Yoon had left the meeting right away.

The martial law decree drew criticism as it included an order for striking doctors to return to work -- a major pending issue for the Yoon government -- or face punishment under the decree.

Cho had said that he did not know why such an order was specified in the decree.

Prosecutors were expected to question Cho on the extent of his knowledge and involvement in the short-lived martial law declaration, such as when he had first learned of the decree and what was discussed at the Cabinet meeting.

Prosecutors are likely to bring in other ministers for questioning.

In a parliamentary hearing Wednesday, Han acknowledged that there were "procedural and substantive flaws" at the Cabinet meeting, which reportedly has left no written record. (Yonhap)