Major Chinese solar panel makers on Thursday protested over punitive tariffs the European Union plans to levy on Chinese-made photovoltaic (PV) products.

Protests at more than 40 solar companies broke out as EU member states begin voting on proposed anti-dumping duties ranging from 37 percent to 68 percent Friday. The provisional rates will be effective from June 6 if the proposal is passed.

Representatives of three solar panel giants, Yingli Green Energy Holdings Co, Trina Solar Ltd and Canadian Solar Inc, held a press conference Thursday in Beijing, lashing out at the EU penalties and calling for free trade.

In a joint statement, the three said any market restrictive measures would hurt China's solar industry, but would also hinder solar application and development in Europe and have a major negative impact on the EU's economy and employment.

According to a research report by German consulting firm Prognos, the punitive duties could lead to job losses of more than 200,000 in Europe over three years.

Some 1,000 workers gathered at a Yingli factory compound in the city of Baoding in northern China's Hebei Province, holding signs of "No Trade Protection." Workers from other solar firms protested across the country.

Meng Xiangan, deputy director of China Renewable Energy Society, criticized the EU's move as trade protectionism and believed that China might take retaliatory measures.

Free trade, fair competition, opening-up and cooperation are the key prerequisites to the healthy development of the global PV industry, said Fan Ruifeng, public relations director of Trina Solar Ltd.