Former senior defense and military officials embroiled in controversy over a military report on the death of a Marine last year refused to be sworn in as witnesses during a parliamentary hearing Friday.

Former defense minister Lee Jong-sup, former vice defense minister Shin Beom-chul and Lim Seong-geun, former commander of the Marine's First Division, were asked if they would refuse to take an oath and all three answered "yes" at the hearing held by the legislation and judiciary committee.

The three former officials expressed their intent to truthfully testify but refused to take an oath on legally guaranteed grounds as they are defendants in an ongoing investigation by the Corruption Investigation Office for High-ranking Officials(CIO). 

Main opposition Democratic Party(DP) Rep. Jung Chung-rae, who chairs the committee, warned that they could face a complaint unless their explanations are justified.

Among 12 witnesses called to Friday's hearing, vice defense minister Kim Seon-ho appeared to replace defense minister Shin Won-sik, while Marine Corps Commandant Lt.-Gen. Kim Gye-hwan was expected to attend virtually.