BRUSSELS (Reuters) - Turkey has launched a legal challenge at the World Trade Organization against curbs on steel imports imposed by the European Union after the effective closure of the U.S. market.

The European Union set quotas on imports of 26 grades of steel in July 2018 over concerns the EU market would be flooded with steel after U.S. President Donald Trump imposed tariffs on steel coming into the United States.

The EU has set import quotas, to run until July 2021, with 25% tariffs applying once those quotas are filled.

Turkey is one of the main exporters of steel to the 27-nation bloc, along with China, India, Russia, South Korea and Ukraine.

Turkey's challenge to the WTO says that the European Commission, which oversees trade policy in the European Union, failed to make adequate findings and conclusions, including that EU producers were threatened with serious injury.

The EU revised its measures in September 2019 in a way seen as hitting imports from Turkey.

Under WTO rules, the two sides have 60 days to try to settle the dispute through consultations, after which time Turkey could ask the WTO to adjudicate.