Venezuelan secret police arrested San Cristobal Mayor Daniel Ceballos on Wednesday.
San Cristobal is the city where anti-government demonstrations began in February. President Nicolas Maduro has been cracking down on protesters.
Interior Minister Miguel Rodriguez claimed Ceballos' arrest was "an act of justice against a mayor, who not only stopped complying with his obligations under the law and constitution, but facilitated and helped all the irrational violence in San Cristobal."
The mayor's political party, Popular Will, denounced the arrest as a "kidnapping."
Human Rights Watch Americas director Jose Miguel Vivanco observed that "The government of President Maduro has engaged in a pattern of persecuting opposition leaders by attributing to them responsibility in criminal cases without showing evidence that links them to the crimes... This is a violation of the basic rules of due process."
The Wall Street Journal reported analyst assessments that Ceballos' arrest could reinvigorate the opposition movement.
Ceballos is the second senior opposition leader to be arrested by the Venezuelan government. Opposition official Leopoldo Lopez was arrested in February and held in detention at a military prison, where he remains.
Anti-government demonstrations began in Venezuela in February, demanding an end to goods shortages, inflation, and high crime. Protesters have accused President Maduro's government of responding violently to their opposition, with at least 20 killed during protests.
[Wall Street Journal]