South Korea's ousted premier said on Thursday that he had opposed suspended President Yoon Suk Yeol's declaration of martial law, testifying for the first time at his former boss's impeachment trial about the events of a night that threw the country into turmoil.

South Korean President Yoon Suk Yeol contested his arrest on rebellion charges in one court and pleaded to preserve his presidency in the other, both cases related to his brief imposition of martial law.

SEOUL (Reuters) - A motorcade carrying South Korea's impeached President Yoon Suk Yeol arrived on Thursday at the Seoul Central District Court, where the embattled leader is due to attend the first hearing of his criminal trial over insurrection charges.