Leaders of both sides of Venezuela’s political divide are calling on their followers to take to the streets on Tuesday, in a sign that the crisis set off by this weekend’s disputed presidential election is intensifying.

The opposition leader María Corina Machado released data that she said showed Edmundo González, the opposition candidate, winning in a landslide, and summoned her followers to a rally n front of the United Nations offices in Caracas.

Jorge Rodríguez, the president of the National Assembly and the head of President Nicolás Maduro’s campaign, also called for massive marches on Tuesday from traditional government strongholds to Miraflores, the presidential palace, after the government declared Mr. Maduro the winner.

“Thousands of us will be out on the streets from all four corners of the globe, who came out on the day of the closing campaign to line all the avenues of this capital,” he said on Monday night. “We are going to Miraflores to defend our right to life, our right to freedom, and, above all, our right to choose and to defend the result of the election.”

On Tuesday, an opposition politician was arrested in Sebucán, east of Caracas, his supporters announced. Videos shared on social media showed Freddy Superlando, a former presidential candidate, being taken away by masked armed men.

The scheduled marches follow a day of tense and spontaneous protests that took place in the capital on Monday. Large groups of young men fanned out from neighborhoods where the government had long enjoyed strong support to demand Mr. Maduro’s ouster after 11 years in power. As they marched through the streets, they tore down his campaign signs and set them on fire.