Venezuelan officials said Friday that they had freed 39 political activists who were jailed for their involvement in protests against the government.

Officials said the activists included the former mayor of the city of San Cristobal, Daniel Ceballos, as reported by Voice of America.

Communications Minister Jorge Rodriguez said earlier Friday that a truth commission was reviewing several cases.

Human rights groups say the government of President Nicolas Maduro has jailed hundreds of people for participating in widespread anti-government demonstrations.

Maduro won a second, six-year term on May 20 in a much-criticized presidential election. Venezuela’s leading opposition parties boycotted the vote and two of their most popular leaders were barred from running in the election.

The United States, along with a dozen neighboring Latin American countries, rejected the vote as fraudulent.

Following the election, Maduro called for some political prisoners to be released. In May, his government freed U.S. national Joshua Holt, who was jailed nearly two years ago on weapons charges that U.S. officials considered bogus.

After Maduro’s re-election, U.S. President Donald Trump signed an executive order restricting U.S.-Venezuelan oil transactions and making it harder for Venezuelan officials to profit from selling off the country’s assets.

Venezuela has suffered from hyperinflation, chronic shortages of food and basic goods, and a collapse of public services as its oil revenues plummeted amid reduced petroleum output and, until recently, low crude prices.

Maduro became president after socialist firebrand ruler Hugo Chavez died of cancer in 2013.