HELSINKI, March 14 (Xinhua) -- European Council President Donald Tusk appealed to U.S. President Donald Trump on Wednesday that the U.S. should not launch a trade war.

Tusk said that his aim is to avoid a trade war between the EU and the U.S. "Any kind of trade war would be against our strategic interests. We have to act, but we do not want to provoke new measures," he said.

"His proposal to impose tariffs on European steel and aluminum is a bad sign for transatlantic relations. Let me be clear: instead of risking a trade war, which he seems eager to wage, we should be aiming for greater cooperation," Tusk said at a joint press conference with Finnish Prime Minister in Helsinki.

"When the president says he is unhappy about too many barriers and tariffs between the EU and the United States, I can understand him. We are not happy either. That is the reason why, a few years ago, we started trade negotiations with the United States," he said.

Tusk was referring to the controversial Transatlantic Trade and Investment Partnership (TTIP) talks which have been paused since Trump's election victory in 2016.

For his part, Finnish Prime Minister Juha Sipila stressed, "We have no interest in widening the current stage into a fully-fledged trade war."

Sipila said the window is now open for free trade talks with other countries. "Now that barriers of trade are being erected, we have to become more active with the part of the world which supports free trade."

He singled out the current talks with the Mercosur, which refers to a trade agreement between the EU and Argentina, Brazil, Paraguay and Uruguay.

Trump last Thursday formally signed proclamations to impose a 25-percent tariff on imported steel and a 10-percent tariff on aluminum, which is scheduled to come into force in 15 days.

The decision has ramped up tensions with its trading partners, leading to a growing wave of protectionism around the globe.