Officials dismissed the strike as an effort to destabilize embattled President Nicolás Maduro’s government.
Leopoldo López, one of the leaders, released a video to announce the strike from the military stockade near Caracas where he has been held for 15 months. In the recording, he also called for a nationwide protest on Saturday to press for a release of political prisoners, the scheduling of congressional elections and an end to “repression and censorship.”
“Go out, hand in hand, brother and sister, without distinctions in ideology or political affiliation, to demonstrate that we are on the side of change for Venezuela,” Mr. López said in the video. His hunger strike began Sunday, two days after Daniel Ceballos, the other leader, stopped eating.