Venezuelans began lining up at supermarkets throughout the country on Saturday to stock up on supplies as they woke to the news that the United States had launched airstrikes on the capital and seized the country’s leader, Nicolás Maduro.

While many stores in Caracas, the capital, were closed, some that opened found dozens of people already waiting outside.

People filled their carts with water, toilet paper and other goods.

Few cars were on the streets, and there were no signs of public transportation. Areas near a military base that had been attacked lacked electricity.

Users of a private internet company, Vnet, reported service outages.

In Caracas’s Plaza Venezuela neighborhood, Alondra, a 32-year-old woman who did not want her last name published because of fears for her safety, said she had just returned to the capital after the December holidays and had no food at home.

“I’m not happy,” she said as she shopped. “I understand how delicate the situation is, and I’m afraid things will get worse in the country.”

Tensions mounted because some people were cutting the line, which was not budging.

“We’ve suffered so much,” she added. “I’m feeling hopeless, thinking that everything could get worse and that we won’t be able to hold out.”

Videos from La Candelaria, in downtown Caracas, showed dozens of people standing in line for food.

At a shop in a public housing complex in the city, about 10 people were lined up to fill water jugs.

In La Guaira, an area near where the strikes took place, residents sent videos showing damage to what appeared to be an apartment building. A local journalist said government supporters had taken control of the block and were prohibiting access.

In Valencia, a city two hours west of Caracas, supermarkets opened early.

Panic buying caused some people to bring two cars to transport all the goods they bought.

“We don’t know what is going on — nobody knows,” said Cecilia Martínez, 47. “But we are five people in my house and my parents are older than 80, so I can’t sit and wait until they say whether there is a curfew or not. That’s why I came here and spent all I had.”

José López, 29, at another store in Valencia, said he had bought two dozen eggs. “There’s a lot of anxiety and uncertainty,” he said.

In Zulia and Táchira, the states on Venezuela’s border with Colombia, 400 miles west of Caracas, people who lined up at supermarkets said their biggest fear was running out of food.

“Thank God we’re far from Caracas, but we’re afraid that bombings might come to Maracaibo, too,” said Martha Rangel, a 63-year-old woman who lives in that city. “I don’t have much money, but I’ll buy some cheese and flour to make arepas and have some at home.”

The governor of the state of Sucre, about 325 miles east of Caracas, appeared at a town square on Saturday morning and called for supporters of the ruling party to gather there later in the day.

“We demand that the entire world speak out against the threat and chaos they have tried to sow in our homeland,” said the governor, Jhoanna Carrillo.

People in Sucre had lined up for gasoline, although many pumps were closed.

Armed civilians who support the government had begun to gather in caravans in Cumaná, the capital city in Sucre, and many people were frightened.

“Everyone knows what that means,” said Alejandro Barreto, 26. “The only thing that matters now is buying food.”