Venezuelan opposition supporters took to the streets again on Monday to protest an economic crisis and a decline in democracy under left-wing President Nicolas Maduro in the first wave of anti-government protests in three years. Demonstrators gathered in several cities to organize a fourth round of protests in 10 days, obstructing the main highway passing through Caracas in the morning until they were dispersed by the National Guard. Opposition leaders have criticized the government for using force to disperse Monday's demonstrations. They referred to the firing of tear gas Interior Minister Nestor Riverol said 18 people had been arrested during the protests, which coincided with a public holiday. He made the remarks in a televised statement. The opposition is demanding a date for provincial elections scheduled for last year as well as a timetable for other elections, including the presidential vote, which is to be held in 2018.