The incident occurred in the city of Valle De La Pascua where unknown persons threw a grenade to a school where a polling station was located, the 2001 media outlet reported. Several minutes earlier a grenade was thrown to another polling station but it has not exploded.
Venezuelan President Nicolas Maduro announced his decision to convene the Constituent Assembly in early May, claiming it would bring peace to the South American country hit by months of violent protests. But his opponents feared it would allow him to bypass the opposition-controlled parliament.
The election comes amid protests that erupted across Venezuela in early April and have claimed the lives of over 110 people. They followed an unsuccessful attempt of the Venezuelan Supreme Court to absorb the legislative power of the country's parliament.