CARACAS, Venezuela — Jailed opposition leader Leopoldo Lopez has begun a hunger strike and is calling for a mass antigovernment protest next weekend. The former Caracas area mayor accused authorities in a video leaked to news media on Saturday of killing dozens of people during 2014 protests. The video leak came after news broke that fellow opposition leader, Daniel Ceballos, was being transferred from the military prison outside Caracas where he was held with Lopez to a public jail away from the capital. U.S.