South Korea’s impeached president, Yoon Suk Yeol, was detained in a major law enforcement operation at the presidential compound Wednesday, defiantly insisting the anti-corruption agency didn’t have the authority to investigate his actions but saying he complied to prevent violence.

Yoon Suk Yeol was arrested and questioned by authorities in relation to a criminal insurrection investigation, saying he was only cooperating with what he called an illegal probe to avoid violence.

President Yoon Suk Yeol was arrested and taken for questioning after more than 3,000 police officers marched on his residence in the early hours of Wednesday.