A vehicle enters President Yoon Suk Yeol's residence in Seoul, Jan. 14. Yonhap

Military personnel on guard duty at the presidential residence will not be mobilized to obstruct investigators from attempting to detain impeached President Yoon Suk Yeol, the defense ministry said Tuesday.

Investigators are expected to make a second attempt to detain Yoon this week over his short-lived martial law imposition, after a failed bid early this month that involved an hourslong standoff between the police and Yoon's security staff at the compound in central Seoul.

"(We) clearly state that the military security unit will focus on its mission to guard the perimeters of the residence and will not be mobilized (to obstruct) the warrant execution," Col. Lee Kyung-ho, a defense ministry spokesperson, said in a briefing.

Lee said the defense ministry has informed the Presidential Security Service (PSS) of its stance, and the agency confirmed it would not mobilize the military unit guarding the residence.

Later in the day, acting Defense Minister Kim Seon-ho reiterated the ministry's opposition to using military personnel to obstruct efforts for Yoon's detainment.

"Deploying military forces to engage in physical action in the enforcement of law would not be justified and is not part of their assigned duties," Kim said in a special parliamentary committee session into Yoon's martial law declaration.

Kim had earlier instructed the military unit at the presidential residence to avoid physical clashes with police in their attempt to detain Yoon.

Police suspect that PSS officials ordered the unit to take part in efforts to block investigators from detaining Yoon during their first attempt on Jan. 3. (Yonhap)