Maduro addressed Lopez at a rally in Caracas, saying, "Turn yourself in coward." Maduro also denounced what he said is a "fascist" plot to oust him from power.
Maduro didn't mention Lopez by name, referring to him only by a frequently-used disparaging nickname.
The president said security forces acting on a February 12 arrest order are now looking for the leader of Wednesday's anti-government protests, which resulted in deadly clashes with police and government supporters. Lopez hasn't been seen since a Wednesday night press conference.