BANGKOK — Thailand’s military junta is targeting a popular new pro-democracy party, accusing its leader of causing disorder that could lead to rebellion even as the seat allotments from last week’s parliamentary elections are being calculated.

The billionaire leader of the Future Forward Party, Thanathorn Juangroongruangkit, was ordered on Wednesday to submit to the police for questioning in the case, which initially opened four years ago. He is accused of helping protesters flee arrest at a demonstration and faces up to seven years in prison.

Mr. Thanathorn, who has built a large following partly through social media, posted the summons on Facebook and Twitter and wrote: “When the dark power won’t leave Future Forward alone.”

“It’s clear now that the old-school political game won’t end after the election, but is only getting more intense, because they’re afraid of Future Forward,” he added. The party came in third in the balloting last week.