EU President Donald Tusk on Tuesday said the bloc would respond to a looming trade war with the US responsibly as he urged Europe to engage with Washington in a constructive manner.
"On this issue, we stand by the European Commission, which is currently holding talks with our American friends on how to exempt the EU from the planned steel and aluminium tariffs," Tusk said in a letter inviting EU leaders to a summit on Thursday and Friday.
"We must prepare for all possible scenarios. As the world's biggest trading power, the EU's response will be responsible and reasonable," he said.
The EU has been on tenterhooks amid fears of a global trade war since US President Donald Trump this month suddenly announced steep duties of 25 percent on steel and 10 percent on aluminium.
The European Commission, the 28-nation EU executive body, has drawn up countermeasures on flagship US products including peanut butter, orange juice and bourbon whiskey if Trump goes ahead.
Trade Commissioner Cecilia Malmstroem, the EU's top trade official, is in Washington to meet US Commerce Secretary Wilbur Ross and other officials to unblock the issue.
Quoting French philosopher Montesquieu, Tusk insisted: "the natural effect of trade is to further peace".
Strong transatlantic relations are paramount for Tusk, a former Polish prime minister and he urged EU leaders to keep a cool head.
"Given the importance of this relationship, we should continue to engage with the US in order to strengthen the transatlantic economic relationship, not weaken it," Tusk said.
This, "despite seasonal turbulences," he stressed.