Syria took a break on Tuesday from its gruesome six-year civil war to announce plans to sign the Paris climate agreement, leaving the United States as the only country to reject the emissions-cutting deal.

The announcement came at the 23rd Conference of the Parties in Bonn, Germany, the world’s biggest climate conference. The non-binding Paris accord, through which signatories pledge to reduce emissions of planet-warming gases over the coming decades, was brokered in 2015, when the annual conference was held in the French capital.

The deal was considered historic because it was the first climate agreement to include the U.S. ― the world’s biggest historic emitter, with by far the largest per-capita carbon footprint ― and China, which currently produces the most carbon pollution on a national level. The U.S. took a lead role in shaping the deal.

Only war-torn Syria and Nicaragua, which protested the agreement’s failure to impose strict demands on major polluters, refused to sign.

But President Donald Trump, who rejects scientists’ warnings about climate change, announced plans to withdraw from the pact in June, insisting developing nations received more benefits and the U.S. got none. In his announcement ― which, under the terms of the deal, fully can’t go into effect until November 2020 ― Trump seemed to conflate the accord with a trade deal, demonstrating what was widely described as a poor understanding of how the Paris agreement actually works.

“Like the playground bully that eventually loses all his friends, Donald Trump has isolated himself on the world stage,” Joe Ware, a spokesman for the charity Christian Aid, said in a statement. “When even Syria, with all its problems, can see the sense of a global climate agreement it really shows how ideologically wedded to climate denialism the US Republican Party has become.”