The new head of Venezuela's opposition-controlled parliament was briefly detained Sunday, just days after he said was willing to replace President Nicolas Maduro.
Juan Guaido was on his way to a rally when intelligence agents intercepted his car north of the capital, Caracas.
He was released about an hour after his arrest and made his way to the rally.
Venezuela's Information Minister claimed the detention was an "irregular procedure" by rogue agents who wanted to help the opposition's cause.
He added the agents would be disciplined.
Maduro was sworn in for a second term late last week.
Critics in the U.S., the EU and many Latin American countries have refused to recognize Maduro's leadership, calling him an illegitimate dictator.