MOSCOW - Russia, a major producer and exporter of aluminum and steel, is working out a response to the US introduction of import tariffs on these items, including slapping duties on some US imports, a senior Russian official said Tuesday.

"If the decision to impose duties is adopted, these measures should be significant," TASS news agency quoted Russian Deputy Industry and Trade Minister Viktor Yevtukhov as saying.

However, he said, this measure may be used only in an extreme case. Before that Moscow intends to start negotiations with the United States to persuade Washington to reconsider its decision.

If the negotiations fail, then Moscow would appeal to the World Trade Organization (WTO) Dispute Settlement Body, Yevtukhov said.

According to WTO rules, the process of settling a dispute may take about 15 months.

The United States introduced from March 23 a 25-percent import duty on steel and a 10-percent import duty on aluminum to protect domestic producers from excessive imports.

The duties were postponed for Canada, Mexico, the European Union, Australia, Argentina, Brazil and South Korea until May 1.

According to Yevtukhov's preliminary assessment, Russia would lose $2 billion for steel and $1 billion for aluminum.

According to official Russian customs data, last year the country exported 8.9 million tons of rolled steel products worth $3.3 billion and 3.48 million tons of aluminum worth nearly $5 billion.

Russia's imports from the United States amounted to $9.1 billion in the first nine months of 2017, an increase of 24.95 percent from the same period of 2016.