A demonstrator is blocked by Bolivarian National police during an anti-government march to the headquarters of the national electoral body, CNE, in Caracas, Venezuela, Wednesday, May 18, 2016. Opposition protesters were blocked from reaching the CNE as they demand the government allow it to pursue a recall referendum against Venezuela's President Nicolas Maduro. (Photo by Fernando Llano/AP Photo)





An anti-government protester is detained by Bolivarian National Police during a march in Caracas, Venezuela, Wednesday, May 18, 2016. (Photo by Ariana Cubillos/AP Photo)





Anti-government demonstrators fight with Bolivarian National police on a pedestrian bridge during an anti-government march toward the headquarters of the national electoral body, CNE, in Caracas, Venezuela, Wednesday, May 18, 2016. (Photo by Fernando Llano/AP Photo)





An anti-government demonstrator holds a sign that reads in Spanish: “Venezuela I want you free” during a march toward the headquarters of the national electoral body, CNE, in Caracas, Venezuela, Wednesday, May 18, 2016. Police blocked protesters trying to reach the CNE to demand a referendum to recall Venezuela's President Nicolas Maduro. (Photo by Ariana Cubillos/AP Photo)





An anti-government demonstrator argues with a Bolivarian National Police officer during a march toward the headquarters of the national electoral body, CNE, in Caracas, Venezuela, Wednesday, May 18, 2016. (Photo by Fernando Llano/AP Photo)





Bolivarian National police fire rubber bullets at anti-government demonstrators trying to march to the headquarters of the national electoral body, CNE, in Caracas, Venezuela, Wednesday, May 18, 2016. (Photo by Fernando Llano/AP Photo)





An anti-government demonstrator is pushed away by Bolivarian National Police who block protesters from reaching the headquarters of the national electoral body, CNE, in Caracas, Venezuela, Wednesday, May 18, 2016. (Photo by Ariana Cubillos/AP Photo)





An anti-government demonstrator in costume lies on the ground, affected by tear gas fired by Bolivarian National Police who kept protesters from reaching the headquarters of the national electoral body, CNE, in Caracas, Venezuela, Wednesday, May 18, 2016. (Photo by Fernando Llano/AP Photo)





An anti-government demonstrator wipes his face after Bolivarian National Police fired tear gas to block protesters from reaching the headquarters of the national electoral body, CNE, in Caracas, Venezuela, Wednesday, May 18, 2016. The opposition is demanding the government allow it to pursue a recall referendum against Venezuela's President Nicolas Maduro. (Photo by Ariana Cubillos/AP Photo)





Anti-government demonstrators try to break through a barrier of Bolivarian National Police in an effort to reach the headquarters of the national electoral body, CNE, in Caracas, Venezuela, Wednesday, May 18, 2016. (Photo by Fernando Llano/AP Photo)





An opposition supporter clashes with riot policemen during a rally to demand a referendum to remove President Nicolas Maduro en Caracas, Venezuela, May 18, 2016. (Photo by Carlos Garcia Rawlins/Reuters)





Opposition supporters carrying Venezuelan flags take part in a rally to demand a referendum to remove President Nicolas Maduro in Caracas, Venezuela, May 18, 2016. (Photo by Carlos Garcia Rawlins/Reuters)





Riot police officers detain a demonstrator on a motorcycle during clashes with opposition supporters in a rally to demand a referendum to remove President Nicolas Maduro in Caracas, Venezuela, May 18, 2016. (Photo by Marco Bello/Reuters)





Riot police officers detain a demonstrator during clashes with opposition supporters in a rally to demand a referendum to remove President Nicolas Maduro in Caracas, Venezuela, May 18, 2016. (Photo by Marco Bello/Reuters)





An opposition supporter carrying a banner that reads “There is not food” shouts to Venezuelan National Guards during clashes in a rally to demand a referendum to remove President Nicolas Maduro in Caracas, Venezuela, May 18, 2016. (Photo by Marco Bello/Reuters)





Opposition supporters shout to Venezuelan National Guards during clashes in a rally to demand a referendum to remove President Nicolas Maduro in Caracas, Venezuela, May 18, 2016. (Photo by Carlos Garcia Rawlins/Reuters)





An opposition supporter covers his face to protect himself from tear gas during clashes with riot police in a rally to demand a referendum to remove President Nicolas Maduro in Caracas, Venezuela, May 18, 2016. (Photo by Marco Bello/Reuters)





Riot police officers clash with opposition supporters in a rally to demand a referendum to remove President Nicolas Maduro in Caracas, Venezuela, May 18, 2016. (Photo by Marco Bello/Reuters)





A riot police officer detains a demonstrator during clashes with opposition supporters in a rally to demand a referendum to remove President Nicolas Maduro in Caracas, Venezuela, May 18, 2016. (Photo by Marco Bello/Reuters)





An opposition supporter carrying a Venezuelan flag kneels in front of National Guards during a rally to demand a referendum to remove President Nicolas Maduro in Caracas, Venezuela, May 18, 2016. (Photo by Carlos Garcia Rawlins/Reuters)





Opposition supporters affected by tear gas try to leave on a motorcycle during clashes with riot policemen during a rally demanding a referendum to remove Venezuela's President Nicolas Maduro in Caracas, Venezuela, May 18, 2016. (Photo by Marco Bello/Reuters)