Venezuelan opposition leader Antonio Ledezma has been returned to house arrest after spending three days in jail, his wife has confirmed.
The mayor of Caracas was detained with fellow opposition leader Leopoldo López after urging protests against a controversial vote held last Sunday.
The constituent assembly the vote set up is to be sworn in on Friday, with more mass protests expected.
The Pope urged President Nicolás Maduro to suspend installing the assembly.
The new assembly will have the power to rewrite the constitution and override decisions by the opposition-controlled congress.
Its members were elected in a vote that was boycotted by the opposition and held amid widespread demonstrations. At least 10 people were killed.
Mr Ledezma’s wife, Mitzy Capriles de Ledezma, said via Twitter early on Friday: “Several minutes ago, Antonio was unexpectedly returned by the Sebin (intelligence agency) to our home.
“We thank the people of Venezuela and the international community for their concern and solidarity.”
The circumstances surrounding Mr López’s detention are unknown.
The pair had been taken to a military prison on Tuesday.
US President Donald Trump had condemned the detentions, saying he held Mr Maduro “personally responsible for the health and safety of Mr López, Mr Ledezma and any others seized”.
The constituent assembly is scheduled to be sworn in later on Friday. Opponents have vowed new mass protests and the office of the attorney general said state prosecutors had filed a case to block the inauguration because of alleged fraud during the vote.
A statement from the Vatican meanwhile called on the government to “prevent or suspend ongoing initiatives such as the new Constituent Assembly which, instead of fostering reconciliation and peace, foment a climate of tension”.
Pope Francis also warned security services they should avoid excessive and disproportionate use of force.
President Maduro insists the poll was a “vote for the revolution”, arguing that the move would create peace and foster dialogue by bringing together different sectors of Venezuela’s polarised society.
Both Mr Ledezma and Mr López were key figures in the wave of protests which swept through Venezuela in 2014 in which 43 people from both sides of the political divide were killed.
They have played a less prominent role in the most recent protests because they have been under house arrest but their video messages still get reported and shared widely on opposition websites.
- 6-year-old leader and founder of the Venezuelan opposition People’s Will (Voluntad Popular) party
- Sentenced to 13 years and nine months in jail in September 2015 for incitement to violence
- Has always denied any wrongdoing, his wife heads an international campaign for his release
- Released from military prison and put under house arrest on 8 July 2017 for “health reasons”
- Published a video on YouTube on 25 July urging Venezuelans to protest against the constituent assembly and the military
- 62-year-old mayor of Caracas
- Arrested February 2015 on charges of supporting an attempted coup, which he denies
- Put under house arrest in April 2015
- Long-standing opponent of President Hugo Chávez and his successor Nicolás Maduro
- Published a video on YouTube on 31 July calling the election for a constituent assembly a “fraud”