Pay protests by garment workers in Phnom Penh appear to be turning increasingly violent, with latest reports from Cambodia suggesting that at least four civilians have been shot dead and 21 injured.

Cambodian human rights group LICADHO today (3 January) described the aggression as the "worst state violence against civilians to hit Cambodia in 15 years."

And it warned of growing civil unrest in the capital in the aftermath of the shootings.

The demonstrations had been running peacefully for nine days since they began in 24 December. But violence began yesterday after a crackdown on striking workers by police and officers from a military special command unit who were seen brandishing metal pipes, knives, AK47 rifles, slingshots and batons.

Ten union leaders, garment workers and monks were arrested in the clashes near the Yak Jin factory in Phnom Penh's Pursenchey district.

LICADHO monitors say they have since witnessed security forces using live ammunition to shoot directly at civilians near the Canadia Industrial Area on Veng Sreng Road.

"These latest horrific developments demonstrate why authorities can no longer afford to ignore the social problems and poor living conditions facing workers in Cambodia today," added Moeun Tola, head of the labour programme at the Community Legal Education Centre (CLEC).

The International Labour Organization (ILO) has joined calls for dialogue to resolve the unrest, pointing out that disruption within the important garment sector "is a cause for significant concern."

It adds that the economic fallout from the protests "may impact significantly on the industry's revenues while tarnishing the country's reputation among international buyers." 

The unrest began after a decision by Cambodia's government advisory body, the Labour Advisory Committee, on 24 December to raise the minimum wage for textile, garment and footwear factory workers to US$160 per month over the next five years.

Trade unions had called for the minimum level to be raised immediately to US$160.

The Garment Manufacturers Association in Cambodia (GMAC) blamed six of the major apparel trade unions and their leaders for the resulting protests that it says caused damage to factories.

GMAC then issued an open letter on Sunday (29 December) recommending its members shut down their factories to avoid violence as strike action escalates.

By Tuesday (31 December), most factories had ceased operations according to the International Labour Organization's Better Factories Cambodia project, based in Phnom Penh.

GMAC secretary general Ken Loo told just-style that the shutdown would continue until "we get assurance from the trade unions as well as the ministry of labour that it is safe for our workers to return to work and that our property is also protected".

This proposed pay increase would see minimum wages rise from US$80 to US$95 per month in 2014 from 1 April. Minimum wages would then rise to US$110 in 2015, US$126 in 2016, US$143 in 2017 and US$160 in 2018.