Demonstrations in recent weeks have erupted in poor districts of Caracas, the capital, which have suffered most from shortages of food and medicine. And there were signs that many from those areas had come to the streets again on Wednesday.

“I live in a barrio, and the people there go around begging for food,” said Beatriz Bustamante, a 61-year-old from the Petare neighborhood, a poor district in which opposition support is strong. Ms. Bustamante blamed the government for rising crime, including the death of her only son, who was killed during a robbery.

Even some of the loyalists sent out by Mr. Maduro said they doubted him. “I don’t understand what is going on” in this country, said DeManuel Hernández, a 24-year-old militia member.

“Some say there’s an economic war, but I’ve also heard that the president doesn’t understand how to control the economy,” he said.

Not far from Mr. Hernández, a crowd had gathered in support of Mr. Maduro. But it numbered only in the few thousands, far less than in previous marches or the huge crowds of the opposition, which shut down highways and the city center.

Still, many there defended the president.