President Barack Obama's administration has sided with American steel producers in an international trade dispute, ruling imported steel reinforcing bar from Mexico and Turkey unfairly undercuts U.S. prices.

Monday's preliminary decision by the U.S. Department of Commerce means companies in Mexico and Turkey will be subject to immediate duties.

A final determination won't be made until summer. But within a week the U.S. government will stop distribution at the nation's borders until a cash bond or deposit is posted.

Steel reinforcing bar is known as steel rebar and is used to reinforce concrete. Steel producers in Mexico and Turkey have denied they're violating trade laws.

The investigation by Commerce's International Trade Administration was launched last fall at the request of U.S. steel producers. Companies from Ohio, Oregon, North Carolina, Florida and Texas filed complaints.