BRUSSELS, March 23 (Reuters) - European Union leaders called on Friday for a temporary exemption from U.S. import duties on steel and aluminium to be made permanent, while cautiously welcoming U.S. President Donald Trump’s decision not to impose them on Europe for now.

Trump said on Thursday he would suspend tariffs for the EU, the United States’ biggest trading partner, as well as Argentina, Australia, Brazil, Canada, Mexico and South Korea. The tariffs are suspended until May 1 as discussions continue.

“I’m pleased they’ve announced a temporary exemption for the EU. What I will be working with my fellow EU leaders today is to see how we can secure a permanent exemption for the EU for those steel tariffs,” British Prime Minister Theresa May told reporters as she arrived at a summit of EU leaders in Brussels.

An EU official said all the leaders at the summit were calling for a permanent exemption as they began their discussions on trade.

The exemption from tariffs, if it is confirmed, followed EU Trade Commissioner Cecilia Malmstrom’s trip to Washington for talks with U.S. Trade Representative Robert Lighthizer and U.S. Commerce Secretary Wilbur Ross.

European leaders have said they want to avert a trade war with the United States, but Belgium Prime Minister Charles Michel underlined an irritation at Trump’s negotiating tactics.

“I have the impression that the U.S. leader wants to negotiate with the European Union by putting a revolver to our temple,” Michel said as he arrived at the EU summit. “That’s not a very loyal way to go about negotiations.”

The European Commission has proposed that, if tariffs are eventually imposed, the bloc should challenge them at the World Trade Organization, consider measures to prevent metal flooding into Europe and impose import duties on U.S. products to “rebalance” EU-U.S. trade. (Writing by Richard Lough; editing by Philip Blenkinsop)