The villagers appeared as silhouettes in the headlights of cars and trucks, a few carrying guns and others clubs, as if they were gangsters roaming the streets.

They were local men and women formed into self-defence units in the villages of the Vinnytsya region in central Ukraine, which had gone silent and dark when the streetlights switched off. They stood by the roadsides, under a very low sky with bright stars.

“I am so proud of our people,” said Oksana Mudryk, the mayor of Khomutyntsi village, about 140 miles southwest of Kyiv, Ukraine’s capital. “Our village is so tiny that I was thinking, ‘Do we even have anybody to patrol the streets?’ I thought maybe three guys at most would come to patrol with me. But in one day after the war started in Kyiv, I have signed up more than 30 people.”

Most of the attention in the first days of the war has focused on Ukraine’s large cities, which are the main targets of Russian troop movements and the scene of pitched street battles and deafening artillery attacks. But out in the countryside, a massive grassroots movement is underway in villages like Khomutyntsi as ordinary Ukrainians — farmers, shop owners, day laborers, taxi drivers — take up arms to join a battle that has abruptly upended their lives.

The mobilization of civilians to fight against seemingly impossible odds has been one of the distinguishing features of Ukraine’s unexpectedly fierce resistance. And though it may end tragically, Ukrainian officials have been pointing to the effort with pride.

“The Russian leadership does not understand that it is at war not only with the armed forces of Ukraine, but with the entire Ukrainian people,” Prime Minister Denys Shmygal said in a news briefing Sunday. “And these people have already risen to the liberation struggle, liberation war against occupiers.”

Displays of defiance have been recorded across the country. In eastern Ukraine, where Russian armoured columns entered towns and villages, some local residents confronted soldiers with angry words. In northern Ukraine, a man knelt briefly in front of a tank. One Ukrainian woman filmed herself on a cellphone taunting a Russian soldier by telling him to put sunflower seeds in his pocket, so that when he died in Ukraine, flowers would grow.

In Khomutyntsi, the big meadow that stretches along the Postolova River is normally a place of leisure. Villagers fish in the river year-round and swim there in the summer. But this weekend the whole village gathered in the meadow to build trenches, a checkpoint and underground shelters.

Mudryk drove her car Saturday night to check on her volunteers. She does this several times each night, as patrols keep guard on the roadsides from dusk to dawn.

Why would the Russian army come to Khomutyntsi, a cluster of one-story, white-plastered homes, garden plots and dirt roads, with about 400 residents, surrounded by forests and fields? It might seem unlikely. But if Russian troops did arrive, they would not go unnoticed by local people on the watch.

“I am crying so much as it is very difficult to get used to our new reality,” Mudryk said. “But I bow my head in honour to our people. Today, we were asked to bring some help with food to soldiers. In two hours, we loaded a full van of food, just from our village.”

There is bravery, but there is also great fear. Standing on the road in the dark, the mayor pointed at a star in the sky that seemed to be behaving strangely, worried it might be a Russian drone over the village.

Serhiy Osavoliuk, who signed up for patrol duty, said his wife soon followed suit. “My wife, probably thinking of controlling me, signed up as well,” he said. “Now we patrol together.” The pair walk about with flashlights, stopping cars and checking who is inside. Usually, it is just local people.

Scenes like these are repeated in village after village through the countryside. Hundreds of local people helped build fortifications, bringing big sacks from their houses and filling them with sand.

Many of the civilians doing support work, like Osavoliuk and his wife, are unarmed, although a few have guns or have asked for them. But it seems as if everybody is doing what they can, hoping that even little actions might help. The national road agency of Ukraine, for example, issued an order to take down all the road signs — to make it harder for Russian troops to navigate.

On the road between the towns of Vinnytsia and Kalynivka, the process had already started, bringing one more, strange new scene on the side of familiar roads. The sign for the village Pysarivka disappeared in just five minutes. Volodymyr, a road service worker, who is 55 and did not want to provide his last name for safety reasons, said he had been driving around tearing down signs. “It is important for them to get lost,” he said of the Russians.

In Kalynivka, which is close to a large weapons depot that Russian troops have targeted, local volunteers wove small strips of cloth together to form a camouflage net over their checkpoint. Too many people have been clustering around the spot, they said, making it a potential target. The location they chose is next to a bomb shelter, to hide in if bombs start to fall.

“We came to help our soldiers,’’ said Valentyna Rudenko. “It is hard to believe it is happening to us.” In some places, as in Hushchyntsi, the volunteer effort encompassed the whole village. About 50 people were piling up logs into makeshift bunkers, as children ran about and women carried out homemade meals.

“Step away, you might get hurt, that’s the job for grown-ups,” one man told the children hoping to participate. The town square near a military recruitment center in Kalynivka was filled with men with duffel bags, and also their wives and children who came to say goodbye.

They sat on tree stumps and on their bags or stood in groups joking. Their children grew bored during their fathers’ long waits to be issued a gun and receive instructions.

Those who were waiting had already registered and came ready to deploy. But there were also newcomers arriving every minute at the entry gate to the square, asking guards where they should go to register.

Among them was Volodymyr Varchuk, 67, who rode up on a rundown bicycle. “Hey guys, how do I sign up?” he asked. Soldiers looked at each other and asked his age. When Varchuk answered, a soldier told him to go away and wait until he is called up.

Varchuk left disappointed. “The young ones will be sent to fight, but us old ones are those who should guard the town!” he said. “I knew it would happen since 2014. We already had war with Russia. It’s obvious they would want to proceed.”

People were running in and out of the recruitment center, with bags of food, water and clothes. One woman with two sons who looked about 20 took them to a bench and had them sit down. Then she helped them try on the new shoes she had bought for them.

An older man named Viktor came to say goodbye to his son. “My soul is restless,” he said. “How would you feel sending your son to the war?”