The opposition says it is a bid by Maduro to concentrate dictatorial prerogatives and stay on despite his deep unpopularity, put at 80 percent by Datanalisis.
The country has been immersed in political, social, and economic turmoil for years, and over the past months, millions of protesters have taken the streets of Venezuela to call for Maduro and his cabinet's resignation. He also has family who have lost personal property to the government. After Chávez died in 2013, Maduro was elected President.
Ex-Bolivian president Jorge Quiroga was among a group of former Latin American presidents who flew to Caracas on Saturday to support the opposition.
Julio Borges, leader of the opposition-controlled legislature in Venezuela, said the vote was a watershed moment "in this fight to win back democracy for Venezuela".
Nelson said that more than 1,200 Venezuelans in San Antonio cast their votes on Sunday.
The country's National Electoral Council said that results of the referendum would not have legal force as only the electoral authorities have the right to hold such events. Tensions have soared across Venezuela amid widespread food and medicine shortages and spiraling inflation that the government routinely plays down.
Last night the votes were sent to Venezuela to be recounted.
The United Nations called on Venezuela's government to let people take part in an unofficial referendum on the constitution on Sunday and make sure security forces do not use excessive force against protestors. "The constitutional assembly is something that benefits the people".
The ANC will have the power to call snap presidential elections.
Nearly 7.2 million Venezuelans took part in the non-binding referendum organized by the country's main opposition parties, with the overwhelming majority of voters coming out against Maduro's plan.
At the same time, Maduro's supporters also cast a ballot - with the government staging a rehearsal of the July 30 constitutional elections.
"Only a political solution can restore hope to Venezuela", he added.
The attack in the working class neighborhood of Catia was being investigated, the public ministry said in a statement. "Liberty!" chanted participants in Spanish at Miami Dade College West Campus in Doral, one of the polling sites. "We assure people that we will continue to look for measures so that they can out and vote peacefully on voting day", Lucena said. "We are slowly losing it. With this new constitution the president is proposing, we are going to see a more autocratic regime and this is what we want to prevent".
Since April, protests have ramped up, and 90 people have been killed.
Neomar Lander's coffin, one of the boys killed in the protests.
All were Venezuelan citizens living here temporarily or with dual U.S. citizenship. "He needs to leave now, that's all", one of them, former Mexican president Vicente Fox, said.
After Faria handed in this electoral ballot, he stood in front of his native country's flag with his Venezuelan identification card in one hand and his voting slip in the other and smiled for the camera.