The US is appealing the World Trade Organization (WTO) decision to reject US tariffs on Chinese goods.
An employee of the WTO announced this on Monday.
Last month, the trade association ruled that the tariffs imposed by the US on Chinese products two years ago are in violation of international trade rules.
According to the WTO, the United States has not been able to demonstrate well enough that China is guilty of "technological theft," which was the reason for the Americans to impose the charges.
The US said shortly after the WTO ruling that it did not agree.
It has now become clear that the Americans are appealing.
They consider the WTO's verdict a "missed opportunity" to tackle China's "aggressive" policies.
The United States started a trade war with China two years ago by imposing import tariffs on various goods from China.
The US imported about 300 billion dollars (254 billion euros) of these goods annually.
The Chinese did not give up and went to the WTO.
US also quarrels with European Union
The US is also at odds with Europe.
This concerns subsidies for aircraft manufacturers.
According to the US, Europe supports the French Airbus, while the European Union believes that the US unjustly supports the American Boeing.
Both camps have therefore introduced import duties on each other's products.
On Monday, a representative of the US government said that he regretted the introduction of these charges by the EU and that it was seeking a joint agreement on the aid that Europe provides to Airbus.
The rulings came after the WTO gave formal permission to the EU on Monday to introduce import tariffs on various US goods.
Every year the EU imports 4 billion euros worth of these goods.