More than 1,000 workers from multiple industries were temporarily stopped from conducting a march to celebrate International Workers’ Day in Phnom Penh yesterday, only to ultimately be allowed to conduct an abbreviated march in the presence of around 100 riot police.

The same event last year had proceeded with a much smaller police presence, and workers had been allowed to march a longer route, with one rights activist suggesting yesterday’s forces had been deployed to “threaten” demonstrators.

Major independent unions had planned to assemble 3,000 workers yesterday at the Russian Embassy on Sothearos Boulevard and march to the National Assembly nearby. But they were greeted with police barricades and around 40 police officers.

“They said [the march] will affect national security. We said ‘we only want to celebrate May Day so what effect does it have on national security?’” said Ou Tepphalin, deputy president of the Cambodian Food and Service Workers Federation (CFSWF).

After nearly two hours of negotiations with local authorities, the unions were allowed to conduct a short march to the Australian Embassy, a few hundred metres shy of the National Assembly, but only after around 100 riot police, equipped with shields, batons and tear gas launchers, were deployed to monitor them.

Municipal spokesman Met Measpheakdey said the march was in defiance of a City Hall ban issued last week, and justified the security response by saying that the demonstrators had marched in an area that had sensitive locations, such as the National Assembly, Foreign Ministry and the Australian and Russian embassies.

“It was to ensure safety. They said to us 3,000 people [will march], so we need to put those police to protect the safety for all,” he said.

But Licadho’s Am Sam Ath, who was monitoring the event, said it was surprising to see the heightened security, which he perceived as a threatening gesture from the authorities on a day where it is common for workers across the world to celebrate their rights.

“If you look at the pictures, it looks like they are there to protect them, but they are here to threaten [workers],” he said.

Riot police armed with tear gas launchers get into formation as more than a thousand workers demonstrate near the National Assembly to celebrate May Day yesterday in Phnom Penh. Pha Lina

See more pictures from the day here.

After reaching the Australian Embassy, union leaders addressed the crowds on a makeshift stage, where they led chants with proworker slogans. Workers wore red headbands, and hoisted union flags and colourful banners with sector-specific demands written on them.

While some demanded Cambodia ratify International Labour Organization conventions to protect domestic workers, others called for an end to worker discrimination and increased protections for female workers, especially those who are pregnant.

Since last May Day, unions have faced the passage of the highly-contentious Trade Union Law, which labour advocates say is being used to restrict factory-level union registrations. While garment worker-related accidents have seen a small dip, around 140 factory closures in 2016 left many workers in the lurch in terms of unpaid wages and severance.

“Our rights have been reduced since the Union Law was approved. If we do not come to protest or to demand our rights, who will know our rights and find a solution for our concerns?” said Yang Sophorn, head of the Cambodian Alliance of Trade Unions.

Union leaders also presented Cambodian People’s Party lawmaker Lork Kheng with a 16-point petition, which included demands for a $207 monthly wage for garment workers, better occupational safety guidelines and revisions to the Trade Union Law.

The lawmaker’s presence at the rally was uncharacteristic, given that unions normally hand over such petitions to the National Assembly’s secretariat. Kheng took the opportunity yesterday to promote the Cambodian People’s Party’s line on workers’ rights.

“The workers are important because they push the country’s economy. The government has pushed hard to increase workers’ wages,” she said.

However, CFSWF President Sar Mora was sceptical of the lawmaker’s claims, saying the unions would only believe her if the government acted on the long-standing demands stated in their petition.