(CNN) -- Bolivian President Evo Morales plans to sign legislation Friday scheduling a May 4 referendum on a new constitution, the Bolivian Information Agency reported.
Bolivians celebrate Thursday in La Paz after Congress decides to call for a referendum on a new constitution.
The move comes after the Bolivian Congress decided Thursday in a raucous session to let people nationwide vote on the controversial plans.
The proposed constitution would strengthen the country's indigenous majority but has faced fierce opposition from nonindigenous Bolivians, including those in four provinces whose governors have declared autonomy.
Hundreds jammed streets Thursday outside the congressional building in La Paz to prevent opposition legislators from entering. Video footage broadcast on CNN en Espaņol showed people pushing, shoving and hitting others. 
Watch as the crowds block the opposition »
Congress made its decision to hold a referendum "with a reduced presence of opposition lawmakers," the Bolivian news agency said.
Opposition legislators decried the move as "illegal," the agency said, but supporters of Morales welcomed it.
"Now it is the Bolivian people who will decide with their vote whether to approve or reject the new constitution," said Vice President Alvaro Garcia Linera, according to the Bolivian Information Agency. E-mail to a friend 
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