A joint investigation team arrives at the Presidential Office in Yongsan District, Seoul, Dec. 16.

A summons asking President Yoon Suk Yeol to appear for questioning over alleged insurrection was delivered to the presidential residence Tuesday but sent back, a joint investigation team said.

The team, which is made up of the police, the Corruption Investigation Office for High-ranking Officials (CIO) and the defense ministry's investigation unit, said the summons was delivered by the postal service but returned shortly thereafter.

Yoon has been asked to appear at the CIO's office in Gwacheon, just south of Seoul, at 10 a.m. Wednesday for questioning on allegations he incited an insurrection and abused his power through his short-lived imposition of martial law on Dec. 3.

The team sent the order by registered mail on Tuesday, the same day its investigators tried to deliver the summons to the presidential office and the presidential residence but failed after the presidential security service refused to cooperate.

"Once a summons arrives, we regard it as the person in question being aware regardless of whether they received it or not," a police official said. (Yonhap)