Venezuela’s opposition-controlled congress named new temporary boards of directors to state-oil firm PDVSA on Wednesday, in an effort to wrest the OPEC nation’s oil revenue from increasingly isolated socialist President Nicolas Maduro.

Maduro lashed out at the Congress leader, Juan Guaido, saying in an interview that he would face the courts “sooner or later” for violating the constitution, after Guaido invoked constitutional provisions last month to assume an interim presidency.

Although many Western countries have recognized Guaido as the legitimate head of state, Maduro retains control of state institutions and Guaido needs funds if he is to assemble an interim government.