Venezuela's opposition on Monday called on its supporters to join escalating protest tactics against the government, including a 24-hour national strike on Thursday.
"The day was stained by the killing of a Venezuelan woman who was protesting and exercising her rights", said opposition leader Freddy Guevara of the killing of Xiomara Escot.
The Venezuelan opposition says more than 7 million people participated in Sunday's referendum.
The referendum Sunday was also marred by violence. The President's call to amend the constitution has led to widespread protests condemning the move.
David Smilde, a Tulane University expert on Venezuela, said Sunday's results would likely rally the global community even more strongly against the July 30 vote Maduro has called to elect members of the assembly that will retool Venezuela's 1999 constitution.
"We have received a clear mandate of 7.1 million to be sure that we will achieve a democratic change".
Cecilia Garcia Arocha, rector of Central University of Venezuela, announced the results at the referendum headquarters in Caracas, pointing out that the number of polling stations, at 2,030, was much lower than in regular elections.
Venezuelans living in Costa Rica take part in an unofficial referendum launched by the Venezuelan opposition in San Jose, Costa Rica, 16 July 2017.
Sunday's unofficial poll was held in improvised polling across Venezuela and in more than 100 countries around the world.More news: Destiny 2 gets limited edition Glacier White PS4 Pro bundle
More news: 'Spider-Man: Homecoming' Swings to $50.5M Friday for $120M-Plus Launch
More news: Trump offers help to parents of sick baby
Venezuelan bishops have warned that President Maduro is seeking to establish a "socialist, Marxist and militaristic" state as tensions continue to rise in the Latin American country.
The total vote would be impossible to check, he said, as opposition organisers were going to burn ballots.
"They have convened an internal consultation with the opposition parties, with their own mechanisms, without electoral rulebooks, without prior verification, without further verification".
"There's kids dying because they are starving, there's no food, there's no medicine", Cabrera said.
One dead and several wounded by gunshots. However, no official vote count was available early Monday.
"It clearly states that Maduro is as deeply unpopular as he has always been thought to be, and it shows, as the polls have suggested, that Venezuelans are overwhelmingly against the idea of establishing a constitutional assembly", Philip reports.
Maduro described the event as the "biggest and most impactful dry run of all dry runs that have taken place in the last 18 years" in a tweet on Sunday.
"They (MUD) have a quiet consultation today (.) I tell them not to go insane, we make a call for them to return to peace, to sit down and talk, to begin a new cycle of dialogue for peace", said Maduro during a telephone interview with the state-owned Venezolana de Televisión.
Late Sunday, the prosecutor-general issued a statement stating that a shooting at the town of Catia, west of Caracas, had killed Scott and three others outside a voting centre.
"Our president Chavez supported the poor, the people", said Yveth Melendez, a 41-year-old homemaker waiting outside a school in the south Caracas neighborhood of El Valle, a stronghold of government support that has been weakening in recent years.