BEIJING -- In early March, hundreds of workers took to the streets in a rural city in China's northeastern Heilongjiang Province, shouting at the top of their lungs and demanding unpaid wages.

A man with a bullhorn was desperately trying to placate them, but the crowd of agitated protesters continued to shout in unison. "Corruption! Embezzlement! Are you starving us to death?" one demonstrator said.

The protest was touched off by a careless and deceitful remark made by a high-ranking local government official at the annual National People's Congress, China's legislature, in Beijing.

The Chinese Communist Party has long used economic growth as the justification for its one-party rule since it adopted the 1979 reform and opening-up policy. However, this model is beginning to falter as the Chinese economy is quickly losing steam. The demonstration that broke out in the city of 1.5 million has underscored the Communist Party's growing sense of alert over rising uncertainty amid economic slowdown.

For years, the city of Shuangyashan, in eastern Heilongjiang Province, prospered thanks to the local mining industry. But the city has seen a steady decline due to China's economic downturn and falling natural resources prices. The Shuangyashan Mining Industry Group, once central to the local economy, experienced financial difficulty and was unable to pay wages to mine workers for five to six months.

While its workers had grown frustrated about their unpaid wages, on March 6 at the National People's Congress, Heilongjiang Gov. Lu Hao said, "There has been no case of wage arrears or unpaid wages."

Hearing this, workers feared they would never be paid. Worries grew about how they would provide for their families. Anxiety turned into anger.

Protest erupts

On March 11, mine workers swarmed around the company's head office in central Shuangyashan. They held banners that read: "We need to live and eat." "Lu Hao is a liar." "Pay our wages!". The protestors marched around the compound and squared off against the police who rushed to the scene. "In total, there were thousands of people," said a shop owner who witnessed the demonstration.

The Communist Party considers such an incident unacceptable, putting foremost priority on stable governance. The protest also dealt a blow to Lu, a promising figure in the party and the youngest provincial leader in China. At a hastily arranged news conference in Beijing, he told reporters, "My comment was wrong. I need to correct my error."

As a result, the mining company promised to pay two months of wages as a temporary measure, and the uproar diminished on March 14.

A week after the incident, a man in his 30s, who lives in a mine workers' residential district one-hour drive from the city center, said "We received the money. It is already a thing of the past." Yet, he gradually raised his voice as he kept talking. "Our wages are a little more than 1,000 yuan ($153) a month. It wouldn't be so much even if the company paid us all back. I mean, the company's executives embezzled our wages," he said.

Another worker in his 40s chimed in. "We just received two months of our pay this time. We don't know when they will pay us the remaining wages," he said.

Ripple effect

Some mine workers also said that laborers from Mudanjiang, about 200km south of Shuangyashan, had taken part in the demonstration. As wage arrears are common among coal mines in many places, miners in Mudanjiang sympathized with the situation and came all the way to participate, workers in Shuangyashan said. This suggests that the protest could have triggered a wave of similar demonstrations in other cities.

Indeed, protests over back wages occurred in at least two other cities while the National People's Congress was in progress -- a very politically sensitive time of the year for China.

According to the U.S.-based Chinese news website Boxun.com, 1,000 or more steelmaker employees gathered outside the company's office on March 14 in the city of Tonghua, China's northeastern Jilin Province. They demanded payment of unpaid wages. Police officers tried to block them from entering the premises, but some managed to climb over the gate wall, the news site said.

On March 17, one day after the National People's Congress ended, about 200 mine workers took to the main street in Chengcheng County, Shaanxi Province, protesting against wage arrears and occupying the street for about one hour, according to Boxun.com. In the end, the police and the company officials turned up and dealt with the situation. Videos and photos of the demonstration were temporarily available on the Internet, but the authorities removed them.

In China, the number of demonstrations and labor strikes came to 2,744 in 2015, the highest on record, according to China Labour Bulletin, a Hong Kong-based organization that surveys the labor environment on the mainland. The figure doubled from the level in 2014, and a 15-fold increase from five years earlier.

Unpaid wages are mostly the cause of all these protests. As the Chinese economy is sputtering, workers have grown ever more frustrated about bleak prospects. "In the end, Chinese citizens rise up only when they feel financial pain," said a diplomatic source in Beijing. "But if such demonstrations ensue in cities across the country, that could fuel social unrest considerably."

The leadership under Chinese President Xi Jinping has pledged to eliminate the so-called state-owned zombie companies, a necessary measure for a country struggling with overcapacity due to the government's massive economic stimulus following the 2008 global financial crisis.

And yet, such a draconian measure, if enacted, would inevitably lead to massive unemployment. "If this issue is handled poorly, it could undermine the party's foundations," a Communist Party official, said.