For the past two weeks, Minsk has been a red and white city. On Saturday afternoon, in the latest in a long series of protests against Alexander Lukashenko’s regime, more than 2,000 women gathered outside a central market, again displaying the familiar colour scheme.

Some wore white dresses with red belts, a few brought white dogs with red ribbons tied on them, and many waved the white-red historical Belarusian flag that has become the symbol of protest over the past fortnight.

The flag – a red horizontal strip between two white ones – has long been seen as the symbol of the nationalist opposition to Lukashenko. Until recently, displaying it in public tended to end in swift arrest.

But over the past weeks, the flag has taken on a new life, as the inspiration for an ever-broader coalition of opponents to Lukashenko. Most fabric shops in Minsk have run out of red and white, as people have scrambled to sew their own flags, but they can also be ordered through the Telegram messaging app.

“It’s wonderful to see all the young people with these flags, many of them have made them themselves,” said Nina Baginskaya, a 73-year-old who has been arrested dozens of times over the years for displaying the flag in public, and is required to pay half of her pension to the state to pay off the accumulated fines. As she stood at the rally on Saturday, younger women came to be photographed with her, and thanked her for the inspiration.

The eruption of protest in Belarus, after a rigged election this month and the police violence that followed in its wake, culminated last Sunday, with the largest demonstration in the country’s recent history. Three enormous red-white flags were unfurled in central Minsk above the heads of tens of thousands of protesters. Another mass rally is planned on Sunday.

After initially appearing overwhelmed by the public reaction, in the past few days, Lukashenko’s regime has mobilised its own support base for a series of counter-rallies with a different colour scheme: the green and red of the country’s official flag. These rallies tend to be smaller, and many of those in attendance are bussed in or appear to be government employees. The standoff between the two flags has become a reflection of the division inside the country, as Lukashenko and his security services fight to cling on to power.

On Saturday, Lukashenko addressed a rally in the western city of Grodno, where a carefully assembled crowd cheered him and waved the red-green flag. He told the crowd that without him the country would collapse in the face of foreign aggression: “We would no longer be our own masters on this square, they would have already chopped us up, chewed us up and spat us out.”

He also visited a military range, where he suggested Nato troops were preparing to invade. “The fatherland is in danger,” he said, reiterating that he had asked Russia’s president, Vladimir Putin, to intervene and help. Putin has so far refrained from direct intervention but on Friday held a meeting of his security council to discuss events in the country.

The red-green flag, which has an embroidered pattern along one side, was introduced in 1951, when Belarus won a seat at the UN despite still being part of the Soviet Union. “Red was the colour of revolution and green was for nature and life. They picked a folk ornament because the Soviets saw Belarus as a nation of peasants,” said the Belarusian historian Aliaksandr Bystryk.

The red-white flag has a longer history, introduced as the flag of the short-lived Belarusian National Republic in 1918. When Belarus won independence from the Soviet Union in 1991, it was readopted, but shortly after Lukashenko came to power in 1994, he held a referendum on returning to the old, Soviet flag in a slightly modified form, without hammer and sickle. Lukashenko’s propaganda focused entirely on the use of the red-white flag by Belarusian Nazi collaborators, ignoring the rest of its history, and displaying it became taboo.

On Friday, a large pro-Lukashenko gathering was held on Victory Square, and a helicopter passed overhead flying a huge red-green flag. One of those at the rally had a sign portraying Adolf Hitler wearing a red-white armband, with the slogan “Don’t let the fascists come back”.

Engineering a confrontation between the two flags appears to be part of Lukashenko’s plan to send a message to Russia that the clash in Belarus is between the legitimate government and radical protesters, rather than a broad, peaceful protest against a police state.

Maria Kolesnikova, the only one of the trio of opposition leaders that formed ahead of elections who still remains in Belarus, said it was possible that the red-green flag could disappear along with Lukashenko, but that for now the protesters had bigger things to worry about.

“I don’t think it can become something that divides society. It’s much more important to deal with economic and political than symbolic issues,” she said in an interview on Saturday.

The regime may have other ideas, however. In a recording leaked last week, the country’s defence minister warned his generals they needed to be ready to shoot in the event of a civil confrontation. Yet while previously, most ordinary Belarusians had a neutral view of the red-green national flag, its association with the convoys of riot police that fly it as they drive through town has turned many away from it.

On the edge of Saturday’s protest, a heated debate broke out over two women who had come clad in both flags, to show that the whole country should unite.

“This is the flag of the torturers, this is the flag of police vans,” shouted an older protester. “It’s his flag, not ours! I never want to see that flag again.”