BEIJING (AP) — China launched two investigations into U.S. trade practices on Friday, signaling its resolve to push back against President Donald Trump’s tariffs ahead of his visit in May.

The Commerce Ministry said the new probes are a response to two investigations announced by Trump earlier this month against multiple countries, including China.

A ministry statement said the two Chinese investigations were launched to safeguard the interests of relevant Chinese industries and expressed “firm opposition” to the American probes.

One will examine U.S. policies that restrict Chinese goods from entering the United States and that limit U.S. export of advanced technology products to China. The other is focused on barriers to Chinese green energy exports.

The probes are expected to take six months and could be extended for another three months if necessary, the ministry said.

The Chinese investigations are the latest volley in a long-running trade war and could be bargaining chips to counter any possible new U.S. tariffs.

The U.S. Supreme Court struck down some of Trump’s earlier tariffs, and he responded by launching what are known as Section 301 trade investigations.

One of those investigations is examining allegations of excess industrial capacity — which can drive up exports — and government subsidies that could give companies in China and elsewhere an unfair advantage over U.S. competitors.

The probe, which targets 16 trading partners, including the European Union, could lead to higher tariffs on imports from those economies.

The other investigation, into dozens of countries, including China, could ban the import of goods made by forced labor.

China’s trade representative warned at recent talks with the U.S. in Paris that the U.S. investigations could threaten a hard-won stability in economic relations between the two countries.

The talks were meant to lay the groundwork for a Trump visit to Beijing, initially due next week. The U.S. president has delayed the trip because of the war in Iran.