(Rueters) -- Opposition supporters protested in Caracas and other cities in what they called "the mother of all marches," denouncing Maduro for eroding democracy and plunging the oil-rich economy into chaos.

Crowds swelled to hundreds of thousands, including Maduro supporters who held a counter-demonstration in the capital at the urging of the president, and clashes were reported across the country during the most sustained protests since 2014.

Maduro says that beneath a peaceful facade, the protests are little more than opposition efforts to foment a coup to end socialism in Venezuela. The opposition says he has morphed into a dictator and accuses his government of using armed civilians to spread violence and fear.

The deaths mean eight people have now been killed during protests in Venezuela this month. The opposition blames the deaths on security forces and alleged paramilitary groups. Over 400 people were arrested during protests on Wednesday, rights group Penal Forum said.

The opposition called for another protest on Thursday, raising the specter of prolonged disruption in Venezuela.