Cabello even helped drive him to custody in his own car given the risks to Lopez's life from extremists, Maduro said.
With local TV providing minimal live coverage of the street unrest, Twitter, Instagram and Facebook have become the go-to media for many Venezuelans desperate for information.
However, many social media users are indiscriminately tweeting images without confirming their origin, leading to manipulation and gaffes including footage of unrest in Egypt and Chile being passed off as repression in Venezuela.
Old photos from past protests are also doing the rounds.
Detractors call Lopez a dangerous and self-serving hothead. He has frequently squabbled with fellow opposition leaders, and was involved in the 2002 coup, even helping arrest a minister.
"I've hardly been in office for 10 months and for 10 months this opposition has been plotting to kill me, topple me," Maduro said. "For how long is the right wing going to hurt the nation?"
Though the majority of demonstrators have been peaceful, a radical fringe have been attacking police, blocking roads and vandalizing buildings. Rights groups say the police response has been excessive, and some detainees say they were tortured.
In a nation split largely down the middle on political lines, 'Chavistas' have stayed loyal to Maduro despite unflattering comparisons with his famously charismatic predecessor. Many Venezuelans fear the loss of popular, oil-funded welfare programs should the socialists lose power.