BRUSSELS — European Union regulators ramped up their investigation into the Chinese solar panel industry Thursday by accusing the Chinese government of unfairly subsidizing panel makers.
The latest step in an increasingly acrimonious battle engulfing the global clean-energy industry came a day after the United States made a final decision to impose duties on billions of dollars of solar products from China over the next five years to shield US producers against lower-priced imports.
It also came after the Chinese government said Monday that it had filed a case with the World Trade Organization accusing some European countries of violating free trade rules with policies that favored the purchase of solar energy equipment produced in Europe.
The European Commission is already investigating whether Chinese manufacturers sold equipment for less than the cost of making it. That antidumping investigation is the biggest case of its kind in terms of value, covering imports from China worth $27 billion.
The investigation announced Thursday covers the same products but focuses on whether Chinese authorities have skewed competitiveness with practices like providing silicon and glass at below-market prices, by offering low-cost loans or financing, or by exempting local companies from regulations.
“The European Commission has found that there is sufficient prima facie evidence to warrant the opening of an investigation,’’ it said in a statement.
The dispute has divided the European and US solar industries.
A number of manufacturers, led by the German company SolarWorld, accuse the Chinese of decimating their businesses by pursuing unfair trade practices. They complained after about a dozen solar panel manufacturers went bankrupt or cut back production on each side of the Atlantic.
But some companies, including many that install and repair solar energy systems, say that punishing the Chinese will make it more difficult to generate jobs and to expand use of solar power as a way to cut pollution and enhance energy independence.
“Thousands of EU jobs would be at stake following a misguided attempt to protect a few manufacturers that present just a small part of the solar value chain,’’ said Thorsten Preugschas, the chief executive of a German company called Soventix, which builds and operates solar plants worldwide.
Chinese manufacturers are also struggling because the Chinese industry is saddled with a glut of products after state-owned banks financed a burst of construction over the last four years that left the country with more than two-thirds of the world’s solar manufacturing capacity.
The European Union will be reviewing two cases of suspected Chinese dumping and subsidies and will consider whether to impose duties that would last five years. A decision could be made within 13 months, according to a European official who briefed journalists on the condition of anonymity after the formal announcement. The commission could impose provisional duties in both cases by spring 2013.
Even so, the official said, the antisubsidy case was not ‘‘purely adversarial’’ and Europeans were ‘‘open to finding a solution’’ that could avoid sanctions.