SEOUL, South Korea — South Korean President Park Geun-hye refused to testify Tuesday in the impeachment trial that will decide her future, prompting the prosecutors to question why she has denied the charges of corruption but will not do so before the court.

After Park's refusal, the Constitutional Court delayed the start of oral arguments and asked her to testify Thursday, when some of her current and former aides are also scheduled to testify.

The court cannot force her to appear but can proceed without her if she twice refuses to appear at the hearings.