A demonstrator sits in front of riot police as opposition supporters and students block a highway in the Altamira neighborhood in Caracas, Venezuela, Monday, April 15, 2013. National Guard troops fired tear gas and plastic bullets to disperse students protesting the official results in Venezuela's disputed presidential election.(AP Photo/Ramon Espinosa) (AP2013)
Opposition supporters and students cross a barricade during clashes with riot police in Caracas, Venezuela, Monday, April 15, 2013. National Guard troops dispersed students protesting the official results of Venezuela's disputed presidential election. Opposition candidate Henrique Capriles has challenged his narrow loss to Nicolas Maduro and is demanding a recount. (AP Photo/Fernando Llano) (AP2013)
Opposition supporters and students confront riot police as they block on a highway in the Altamira neighborhood of Caracas, Venezuela, Monday, April 15, 2013. National Guard troops dispersed students protesting the official results of Venezuela's disputed presidential election. Opposition candidate Henrique Capriles has challenged his narrow loss to Nicolas Maduro and is demanding a recount. (AP Photo/Ramon Espinosa) (AP2013)
Demonstrators run from tear gas fired by National Guard as they protest against the official results of last Sunday's presidential elections in downtown Caracas, Venezuela, Monday, April 15, 2013. National Guard troops fired tear gas and plastic bullets to disperse demonstrators protesting the official results in Venezuela's disputed presidential election.(AP Photo/Ramon Espinosa) (AP2013)
Simpatizantes de la oposición y estudiantes confrontan a policías antidisturbios mientras bloquean una autopista en el barrio de Altamira, Caracas, Venezuela, el lunes 15 de abril del 2013. Las tropas de la Guardia Nacional dispersaron a los que protestaban por los resultados de la elección presidencial especial del domingo, cuyos estrechos resultados a favor del oficialista Nicolás Maduro fueron rechazados por el candidato opositor Henrique Capriles, quien demandó un conteo de todos los votos. (AP Foto/Ramon Espinosa)
Opposition supporters confront riot police as they block on a highway in the Altamira neighborhood of Caracas, Venezuela, Monday, April 15, 2013. National Guard troops dispersed students protesting the official results of Venezuela's disputed presidential election. Opposition candidate Henrique Capriles has challenged his narrow loss to Nicolas Maduro and is demanding a recount. (AP Photo/Ramon Espinosa) (AP2013)
Demonstrators take cover from teargas fired by the National Guard as they protest against the official results of last Sunday's presidential elections in downtown Caracas, Venezuela, Monday, April 15, 2013. National Guard troops fired tear gas and plastic bullets to disperse demonstrators protesting the official results in Venezuela's disputed presidential election.(AP Photo/Ramon Espinosa) (AP2013)
Demonstrators, one holding a poster of opposition presidential candidate Henrique Capriles, shout slogans against the government and the official election results in the Altamira neighborhood in Caracas, Venezuela, Monday, April 15, 2013. National Guard troops fired tear gas and plastic bullets to disperse demonstrators protesting the official results in Venezuela's disputed presidential election.(AP Photo/Ramon Espinosa) (AP2013)
National Guards soldiers help a woman trapped between police and demonstrators as opposition supporters and students try to block a highway in the Altamira neighborhood of Caracas, Venezuela, Monday, April 15, 2013. National Guard troops dispersed students protesting the official results of Venezuela's disputed presidential election. Opposition candidate Henrique Capriles has challenged his narrow loss to Nicolas Maduro and is demanding a recount. (AP Photo/Fernando Llano) (AP2013)
Riot police charges towards demonstrators as opposition supporters and students on a block a highway in the Altamira neighborhood of Caracas, Venezuela, Monday, April 15, 2013. National Guard troops dispersed students protesting the official results of Venezuela's disputed presidential election. Opposition candidate Henrique Capriles has challenged his narrow loss to Nicolas Maduro and is demanding a recount. (AP Photo/Fernando Llano) (AP2013)
Opposition supporters burn garbage during clashes with riot police in Caracas, Venezuela, Monday, April 15, 2013. National Guard troops dispersed students protesting the official results of Venezuela's disputed presidential election. Opposition candidate Henrique Capriles has challenged his narrow loss to Nicolas Maduro and is demanding a recount. (AP Photo/Fernando Llano ) (AP2013)
Opposition supporters burn garbage during clashes with riot police in Caracas, Venezuela, Monday, April 15, 2013. National Guard troops dispersed students protesting the official results of Venezuela's disputed presidential election. Opposition candidate Henrique Capriles has challenged his narrow loss to Nicolas Maduro and is demanding a recount. (AP Photo/Fernando Llano) (AP2013)
Riot police charges towards demonstrators as opposition supporters and students block a highway in the Altamira neighborhood in Caracas, Venezuela, Monday, April 15, 2013. National Guard troops fired tear gas and plastic bullets to disperse demonstrators protesting the official results in Venezuela's disputed presidential election.(AP Photo/Fernando Llano) (AP2013)
Venezuela's interim President Nicolas Maduro holds the official certificate declaring him winner of the presidential election at the Electoral Council in Caracas, Venezuela, Monday, April 15, 2013. Venezuela's government-friendly electoral council has quickly certified the razor-thin presidential victory of Hugo Chavez' hand-picked successor. Nicolas Maduro was elected by a margin of 50.8 percent to 49 percent over challenger Henrique Capriles. (AP Photo/Ariana Cubillos) (AP2013)
Opposition supporters shout slogans against Venezuela's interim President Nicolas Maduro during a protest in Caracas, Venezuela, Monday, April 15, 2013. National Guard troops dispersed students protesting the official results of Venezuela's disputed presidential election. Opposition candidate Henrique Capriles has challenged his narrow loss to Nicolas Maduro and is demanding a recount. (AP Photo/Fernando Llano) (AP2013)
Opposition supporters shout slogans against Venezuela's interim President Nicolas Maduro during a protest in Caracas, Venezuela, Monday, April 15, 2013. National Guard troops dispersed students protesting the official results of Venezuela's disputed presidential election. Opposition candidate Henrique Capriles has challenged his narrow loss to Nicolas Maduro and is demanding a recount. (AP Photo/Fernando Llano) (AP2013)
Demonstrators confront the National Guard as they protest against the official results of last Sunday's presidential elections in downtown Caracas, Venezuela, Monday, April 15, 2013. National Guard troops fired tear gas and plastic bullets to disperse demonstrators protesting the official results in Venezuela's disputed presidential election.(AP Photo/Ramon Espinosa) (AP2013)
Simpatizantes de la oposición y estudiantes escapan del gas lacrimógeno después de chocar con la policía antidisturbios cuando intentaban bloquear una autopista en el barrio de Altamira, Caracas, Venezuela, el lunes 15 de abril del 2013. Las tropas de la Guardia Nacional dispersaron a los que protestaban por los resultados de la elección presidencial especial del domingo, cuyos estrechos resultados a favor del oficialista Nicolás Maduro fueron rechazados por el candidato opositor Henrique Capriles, quien demandó un conteo de todos los votos. (AP Foto/Ramon Espinosa)
A demonstrator throws a fire bomb during clashes with National Guard as they protest against the official results of last Sunday's presidential elections in downtown Caracas, Venezuela, Monday, April 15, 2013. National Guard troops fired tear gas and plastic bullets to disperse demonstrators protesting the official results in Venezuela's disputed presidential election.(AP Photo/Ramon Espinosa) (AP2013)
A demonstrator holds a poster of opposition presidential candidate Henrique Capriles as as other Capriles supporters and students block a highway in the Altamira neighborhood in Caracas, Venezuela, Monday, April 15, 2013. National Guard troops fired tear gas and plastic bullets to disperse students protesting the official results in Venezuela's disputed presidential election.(AP Photo/Fernando Llano) (AP2013)