South Korea's suspended president authorised the military to fire their weapons to enter parliament during his failed martial law attempt, according to a prosecutors' report.

South Korea’s President Yoon Suk Yeol again declined to appear for questioning by investigators over his martial law declaration as the embattled leader seeks to first defend himself at an impeachment trial.

A summons for Mr Yoon to appear for questioning over alleged insurrection was delivered to the presidential residence on Tuesday but returned, the agency quoted a joint investigation team as saying. If he responds to the summons, it will be the first time in history that a sitting president appears before prosecutors as a suspect.