Venezuelans march to prison to demand freedom for activists

Relatives of inmates stand on the road leading to the Ramo Verde military prison in Los Teques, outskirts of Caracas, Venezuela, Friday, April 28, 2017. Venezuela's opposition has called for a march to the prison where opposition leader Leopoldo Lopez is serving a nearly 14-year sentence for his role leading anti-government demonstrations in 2014. (AP Photo/Ariana Cubillos) (The Associated Press)

A Bolivarian National Guard officer guards the road leading to the Ramo Verde military prison in Los Teques, outskirts of Caracas, Venezuela, Friday, April 28, 2017. Venezuela's opposition has called for a march to the prison where opposition leader Leopoldo Lopez is serving a nearly 14-year sentence for his role leading anti-government demonstrations in 2014. (AP Photo/Ariana Cubillos) (The Associated Press)

A woman cries during an homage to Juan Pablo Pernalete in Caracas, Venezuela, Thursday, April 27, 2017. Pernalete, the latest victim of Venezuela's unrest, was killed during anti-government protests Wednesday when he was struck by a tear gas canister fired by security forces. (AP Photo/Ariana Cubillos) (The Associated Press)

Hundreds of opponents of President Nicolas Maduro are marching to a military prison outside Caracas to demand the release of Leopoldo Lopez and other jailed activists they consider political prisoners.

Friday's march is part of an intensifying campaign by the opposition to force Maduro from office. Already 28 people have been killed and more than 400 injured in almost four weeks of street clashes between protesters, security forces and pro-government groups.

Light armored vehicles and national guardsmen are blocking access to the facility where Lopez is serving a nearly 14 year sentence for inciting violence during a previous round of anti-government unrest in 2014.

His wife Lilian Tintori was at the front of a group carrying a large Venezuelan flag making its way to the prison.