The European Union's trade deal with the United States that triggered market jitters and a slide in the value of the euro was the best that could be hoped for, says the bloc's commissioner for trade and economic security.

Maros Sefcovic admitted the deal was imperfect, but said, "This is clearly the best deal we could get under very difficult circumstances."

He said Sunday's agreement between European Commission President Ursula von der Leyen and US President Donald Trump was a compromise, which means the two sides — accounting for almost one-third of global trade — avoided a damaging trade war.

However, the deal, which calls for an across-the-board 15 percent tariff on EU exports to the US, and zero percent tariffs on US exports to the EU, has been attacked by Germany's Chancellor Friedrich Merz, who said it will cause the German economy "considerable damage".

And French Prime Minister Francois Bayrou agreed, saying it amounted to a "dark day" for the EU.

Nevertheless, Sefcovic said the deal, which excludes some agricultural produce — including beef, poultry and sugar — was better than the 30 percent tariff Trump had threatened.

However, with the 15 percent tariff far higher than the 4.8 percent average tariff in place before Trump came to power, Terry Reintke, co-president of Germany's Greens, said it means the EU bowed to "the bullying tactics and threats" of Trump.

Sefcovic insisted, however, that "it's quite obvious that the world which was there … is gone".

He said, "We simply need to adjust, we need to address the challenges which are coming from this new approach, and I believe that the strategic cooperation with our strategic partner is a better outcome than an all-out trade war."

Belgium's Prime Minister Bart De Wever said the avoidance of an all-out trade war was good news, but "this is a moment of relief, but not of celebration".

"Tariffs will increase in several areas, and some key questions remain unresolved," he said.

Spain's Prime Minister Pedro Sanchez said that while he supports the deal, he does so "without any kind of enthusiasm".