GUANGZHOU, April 3 -- Police detained 18 people for public order offences during a protest against a paraxylene (PX) project in south China's Guangdong Province.

Liang Luoyue, deputy mayor of Maoming City, told a Thursday press conference that the violence began with a few suspects throwing plastic bottles and eggs at police on Sunday afternoon during a protest by more than 1,000 locals against the chemical plant.

At around 8:00 p.m., more than 40 people attacked two cars in the city square across from government headquarters and assaulted police. Two hours later, stones and bottles were hurled at the gates of the government building, shops and billboards were vandalized, and a police wagon set on fire, Liang said.

Zhou Peizhou, deputy director of Maoming Public Security Bureau, denied reports that 15 people had died and 300 were hurt in clashes between police and demonstrators, saying that despite some scuffles, nobody was dead.

Zhou added that 15 people, including 4 police, who were hurt in the violence and sent to hospital. Sven who remain in hospital are in stable conditions.

Liang Luoyue met with protesters' representatives on Tuesday afternoon and reaffirmed the promise of public consultation.

Liang said the government will strengthen communication with residents and expand channels for them to express their demands through meetings with government officials, the media and on the Internet. The Maoming government's commitment to the PX project is strong, as shown in the 100,000 brochures sent to local homes.

"The PX project will bring about 10,000 jobs and increase tax revenues by 674 million yuan (110 million U.S. dollars) every year," the brochures read, claiming PX is a combustible chemical with low toxicity and no evidence to link it with cancer. The government has run a publicity campaign since late February in local newspapers, trying to dispell fears of the project's safety.

Since 2007, PX projects planned in Xiamen, Dalian, and Kunming have been halted after residents complained, believing the factories would threaten the local environment.

PX is a major raw material in polyester.

There will be a shortage of up to 9.5 million tonnes of PX in China this year, according to a report by China Petroleum and Chemical (Sinopec) Corp., a state-owned oil refiner. The domestic PX industry only met 47 percent of demand in 2013, according to the report.

Maoming is a major petrochemical production base. The PX project was approved in 2012 with an annual production capacity expected at 600,000 tonnes, according to media reports.