(Adds timing of duties)
WASHINGTON, April 21 (Reuters) - The U.S. Commerce Department on Monday set preliminary duties on millions of dollars worth of imports of steel rebar from Mexico and Turkey after a complaint by U.S. producers about price undercutting by foreign competitors.
The department set dumping duties of up to 66.7 percent on imports from Mexico and duties of up to 2.6 percent on Turkish imports after American producers alleged companies from the two countries were selling steel rebar, which is used to reinforce concrete, at unfairly low prices. A final decision is due on July 2.
The U.S. International Trade Commission and the Commerce Department launched investigations after a petition was filed last year by Nucor Corp, Commercial Metals Co and other manufacturers. The trade commission found there was reasonable indication the imports are harming local firms.
Nucor Chief Executive John Ferriola told U.S lawmakers in March that imports from Mexico and Turkey had doubled since 2010 and were having a "devastating" impact on the industry.
Commerce said in 2013, imports of steel concrete reinforcing bar from Mexico were valued at an estimated $182.1 million and from Turkey at $381.3 million.
The manufacturers accuse Mexican and Turkish competitors of unfairly undercutting U.S. prices to grab sales and market share, a trade strategy known as "dumping."
U.S. manufacturers also claimed rebar imports from Turkey were subsidized by the Turkish government, but Commerce ruled in February that this was not the case.
Monday's preliminary ruling set duties of 66.7 percent on goods from Mexico's Grupo Acerero S.A. de C.V. while Grupo Simec received a preliminary dumping margin of 10.66 percent. All other producers and exporters in Mexico received a preliminary dumping margin of 20.59 percent.
Turkish goods will face a duty of 2.64 percent, except for those from Habas Sinai ve Tibbi Gazlar Istihsal Endustrisi A.S., which was excused.
Duties will apply on goods from Grupo Simec and Turkey's Icdas Celik Enerji Tersane ve Ulasim Sanayi A.S from next week. Duties on other imports will be backdated 90 days, to start in late January.
In a second high-profile steel case, U.S. producers have urged Commerce to reconsider a February ruling that found no dumping of steel tube for the oil and gas industry from South Korea, although preliminary duties were set on imports from countries including Turkey and Vietnam. (Reporting by Krista Hughes; Editing by Steve Orlorfsky and Lisa Shumaker)