CARACAS, Venezuela — Antonio Ledezma, a prominent opposition leader in Venezuela who had been placed under house arrest on sedition charges, escaped on Friday morning and fled to neighboring Colombia, where the authorities allowed him to enter.

Calling the trip “an odyssey” and likening it to a movie plotline, Mr. Ledezma, in a brief televised interview after his border crossing, said that he had somehow managed to evade detection while passing through more than 29 posts manned by members of Venezuela’s security forces.

“I am going to defend the liberty of Venezuela,” he told reporters in Colombia. “I’m more useful to Venezuela in the street.”

Mr. Ledezma’s flight was hailed by Venezuela’s political opposition and its sympathizers around the world as a boost for their fight and a major embarrassment for the administration of President Nicolás Maduro, who, with the support of loyal jurists, has sought to silence opponents through imprisonments and other means, including the creation of a new legislative body that essentially neutered the old one dominated by opposition parties.