South Korean police have questioned Prime Minister and Acting President Han Duck-soo as part of an investigation into the short-lived decision this month to impose martial law, an official at his office said on Friday.

South Korean investigators on Friday pressed ahead with their probe into impeached President Yoon Suk Yeol over his Dec. 3 martial law declaration, issuing another summons demanding that he appear for questioning on Christmas Day,

For the United States, the turmoil in South Korea is potentially disruptive to its geopolitical agenda in East Asia.