Venezuela's acting President Nicolas Maduro (front) participates in a ceremony of his official registration as the ruling United Socialist Party of Venezuela (PSUV)'s candidate for presidential elections of April 14, at Venezuela's National Electoral Council (CNE) in Caracas, capital of Venezuela, on March 11, 2013. (Xinhua/David de la Paz)

Venezuela's acting President Nicolas Maduro (R) participates in a ceremony of his official registration as the ruling United Socialist Party of Venezuela (PSUV)'s candidate for presidential elections of April 14, at Venezuela's National Electoral Council (CNE) in Caracas, capital of Venezuela, on March 11, 2013. (Xinhua/Guillermo Arias) 

 Venezuela's acting President Nicolas Maduro (front) participates in a ceremony of his official registration as the ruling United Socialist Party of Venezuela (PSUV)'s candidate for presidential elections of April 14, at Venezuela's National Electoral Council (CNE) in Caracas, capital of Venezuela, on March 11, 2013. (Xinhua/David de la Paz)

Venezuela's acting President Nicolas Maduro participates in a ceremony of his official registration as the ruling United Socialist Party of Venezuela (PSUV)'s candidate for presidential elections of April 14, at Venezuela's National Electoral Council (CNE) in Caracas, capital of Venezuela, on March 11, 2013. (Xinhua/Guillermo Arias)

Venezuela's acting President Nicolas Maduro (L) participates in a ceremony of his official registration as the ruling United Socialist Party of Venezuela (PSUV)'s candidate for presidential elections of April 14, at Venezuela's National Electoral Council (CNE) in Caracas, capital of Venezuela, on March 11, 2013. (Xinhua/David de la Paz)

 Venezuela's acting President Nicolas Maduro (R rear) and Venezuelan Parliament President Diosdado Cabello (R front) take part in a rally held after his official registration as candidate for presidential elections of April 14, outside the headquarters of the National Electoral Council of Venezuela in Caracas, capital of Venezuela, on March 11, 2013. (Xinhua/Guillermo Arias)

Venezuela's acting President Nicolas Maduro (L front) and Venezuelan Parliament President Diosdado Cabello (R front) take part in a rally held after his official registration as candidate for presidential elections of April 14, outside the headquarters of the National Electoral Council of Venezuela in Caracas, capital of Venezuela, on March 11, 2013. (Xinhua/Guillermo Arias)

Venezuelan Parliament President Diosdado Cabello (L) takes part in a rally held after Venezuela's Acting President Nicolas Maduro's official registration as candidate for presidential elections of April 14, outside the headquarters of the National Electoral Council of Venezuela in Caracas, capital of Venezuela, on March 11, 2013. (Xinhua/Guillermo Arias)

Supporters take part in a rally held after Venezuela's acting President Nicolas Maduro's official registration as candidate for presidential elections of April 14, outside the headquarters of the National Electoral Council of Venezuela in Caracas, capital of Venezuela, on March 11, 2013. (Xinhua/David de la Paz)

Venezuela's acting President Nicolas Maduro shows his official registration as candidate for presidential elections of April 14, outside the headquarters of the National Electoral Council of Venezuela in Caracas, capital of Venezuela, on March 11, 2013. (Xinhua/Guillermo Arias)

Supporters take part in a rally held after Venezuela's acting President Nicolas Maduro's official registration as candidate for presidential elections of April 14, outside the headquarters of the National Electoral Council of Venezuela in Caracas, capital of Venezuela, on March 11, 2013. (Xinhua/David de la Paz)

Supporters flutter a giant national flag during a rally held after Venezuela's Acting President Nicolas Maduro's official registration as candidate for presidential elections of April 14, outside the headquarters of the National Electoral Council of Venezuela in Caracas, capital of Venezuela, on March 11, 2013. (Xinhua/Juan Carlos Hernandez)

Supporters take part in a rally held after Venezuela's Acting President Nicolas Maduro's official registration as candidate for presidential elections of April 14, outside the headquarters of the National Electoral Council of Venezuela in Caracas, capital of Venezuela, on March 11, 2013. (Xinhua/David de la Paz)

Supporters take part in a rally held after Venezuela's Acting President Nicolas Maduro's official registration as candidate for presidential elections of April 14, outside the headquarters of the National Electoral Council of Venezuela in Caracas, capital of Venezuela, on March 11, 2013. (Xinhua/David de la Paz)