The U.S. International Trade Commission voted 6-0 that there was a reasonable indication that U.S. manufacturers are injured by imports of "oil country tubular goods" (OTCG) from the nine countries. That allowed the probe to proceed.

The Commerce Department launched the investigation last month, acting on a petition filed by U.S. Steel, Maverick Tube Corporation, TMK IPSCO and other manufacturers who accuse their foreign competitors of unfairly undercutting U.S. prices to grab sales and market share.

The main U.S. steel industry group, the American Iron and Steel Institute, praised the vote.

"U.S. companies and their workers deserve to have a fair shake, and we applaud today's vote as an important move towards providing U.S. steel producers relief from unfairly traded OCTG imports," the group's president Thomas Gibson said.

But a rival organization representing steel importers criticized the action, arguing the U.S. OCTG sector is currently profitable even if "some overly aggressive suppliers (have) created an inventory overhang in the U.S. market."

"With a profitable and growing industry in the U.S., along with growing demand for OCTG from all sources, domestic and imported, this is not an industry that needs trade protection," said David Phelps, president of the American Institute for International Trade.

The Commerce Department will make a preliminary decision on duties in coming months and a final decision in 2014. Other countries named in the case are the Philippines, Saudi Arabia, Taiwan, Thailand, Turkey, Ukraine and Vietnam.