The US commerce department has increased anti-subsidy tariffs on imports of solar cells from China but has held or cut anti-dumping duties on the same products in a case which has heightened trade tensions between the two nations.

The cases have divided the US solar industry between those with significant manufacturing operations in America and those dependent on imports from China, and provoked retaliatory action from Beijing.

The commerce department said on Wednesday that it would impose anti-subsidy “countervailing duties” against solar cell imports ranging, by manufacturer, from 14.78 per cent to 15.97 per cent – significantly higher than the preliminary duties ranging from 2.9 per cent to 4.73 per cent it announced in March. But in a separate decision, it held or cut antidumping duties – used against imports it deems priced unfairly low – from preliminary rates announced in May.