BOGOTÁ, Colombia — The Venezuelan government said Wednesday that it would hold a snap presidential election on April 22, putting the unpopular administration of President Nicolás Maduro in the hands of voters at a time when most top challengers have been barred from running.

The announcement was made by Tibisay Lucena, the president of the country’s electoral commission, who said the date had been chosen after negotiations with opposition politicians had failed to reach an agreement about how to conduct the election fairly.

The election will allow Venezuelans to “freely decide their fate,” she said. “We are committed, as always, to our constitutional task, to guarantee the right conditions so that democratic differences are settled through an efficient, transparent and balanced vote.”

It is unclear whether opposition parties will participate in the election, in which Mr. Maduro will seek another six-year term. Venezuela is now governed by a Constituent Assembly composed of Mr. Maduro’s allies; creation of the assembly sidelined the opposition-controlled Congress and led the country’s closest neighbors to warn that a dictatorship was being established.