Trade frictions between the United States and the European Community heated up yesterday as U.S. officials stiffened curbs on steel imports from Western Europe.

It was a counter-retaliatory move following EC retaliation last week for earlier U.S. curbs on European steel sales.

"It's an unsatisfactory state of affairs, but it is up to the United States to bring us back to a mutually satisfying solution," said Willy de Clercq, EC Commissioner for external relations and trade policy.

Deputy U.S. Trade Representative Alan Woods said the new curbs were "in response to the EC's unjustified, unnecessary and unfriendly retaliation" against American shipments of fertilizer, coated paper and animal fats to Western Europe.

"We are particularly distressed that the EC took this dispute beyond steel into other industry sectors," Woods added.

The dispute began Dec. 30, when the United States placed quotas on EC shipments of semifinished-steel products, which had soared from 3.9 percent in 1982 to 29.9 percent in 1984. Despite the sharp increase in European sales, de Clercq called the limits "unjustified."

He said they would cost EC steel producers $48 million and vowed to retaliate. He said the U.S. actions ran contrary to a new steel agreement concluded Oct. 31.

Woods, however, said the new arrangement gave the United States the right "to protect ourself" by restricting shipment of semifinished steel. He said the Europeans refused to recognize the importance of limiting imports of semifinished steel to President Reagan's attempts to pressure domestic steel makers to modernize and become internationally competitive.

The European Community, however, argued that American steel makers buy the semifinished steel for further processing in this country; therefore, there can be no injury to the American steel industry and no need for government restraints, the EC argues.

The Dec. 30. U.S. restrictions limited EC shipments of semifinished steel to 600,000 tons a year.

Yesterday, Woods said the United States will tighten enforcement of those limits. The EC will be restricted to 150,000 tons a quarter, and will not to allowed to carry over any unused quota to the next quarter. In addition, Woods said, the United States will not allow any flexibility in trading shipments of one product instead of another.

"This is a measured response to a totally unjustified action by the EC," said Woods. "They had absolutely no reason to retaliate against our earlier action on semifinished steel."

The EC restrictions will cut U.S. sales of fertilizer by 23 percent, fats by 20 percents and coated paper used for milk cartons by 8 percent. They will affect about $43 million in U.S. sales a year, and take effect Feb. 15.