The World Trade Organization opened a formal investigation Friday into allegations by the U.S. and Mexico that China is providing illegal subsidies for a range of industries.

The two countries accuse Beijing of using WTO-prohibited tax breaks to encourage Chinese companies to boost exports, while imposing tax and tariff penalties to limit purchases of foreign products in China.

Beijing blocked a separate probe of its rules for protecting intellectual property rights. But the move will probably only delay the creation of a panel until the next meeting of the WTO’s dispute body in September, when Washington can bring up the issue again.