Germany's Chancellor Angela Merkel is preparing for battle with the U.S. President Donald Trump at the G20 summit in Hamburg in a seven days time.
Speaking to the German parliament, Merkel said the European Union stands fully behind its commitment to the Paris Climate Change deal.
Trump withdrew the U.S. from the agreement at the start of June.
“We cannot expect easy discussions on climate change at the G20 summit,” Merkel said. “Our differences with the U.S. are clear."”
She added that “the Paris agreement is irreversible and it is not negotiable.”
The chancellor said that nations turning to isolation and protectionism are making a serious mistake and showcased a renewed “spirit of unity” in the EU after the U.K.'s decision to leave.
The French President Emmanuel Macron later reaffirmed his country's commitment to the climate deal but struck a less combative note.
“It’s pointless to isolate one country,” Macron said.
While Trump needs to be told that Europe disagrees with his stance on climate change, “it’s always preferable to come up with joint statements,” Macron said.
On June 1, Trump announced that he was pulling out of the deal to protect the U.S. economy from an agreement that would cost American jobs.
He also said he’s open to renegotiating the deal on more favourable terms but it’s not clear what that means or if any other country will take him up on the offer.
In a separate development, Germany's Constitutional Court has ruled that the city of Hamburg cannot completely ban a camp in a municipal park where more than 10,000 demonstrators are planning to gather during the G20 summit.
It said the protest camp should be allowed to the greatest extent possible but must try to prevent lasting damage to the area and denting public finances.
The courts are continuing to review other protest activities planned during the meeting.
German police are bracing for massive rallies and demonstrations, with some 20,000 police officers being deployed.
Dozens of protest events, from water-based demonstrations to blockades of the summit venue, are planned.
The largest demonstration, "G20 Not Welcome Here" on July 8, is expected to attract tens of thousands of participants.
Merkel chose Hamburg, the city where she was born before her father moved the family to communist East Germany, as the location for the summit to send a message of openness to the world.