President Donald Trump's pullout from the Paris climate accord has triggered a bipartisan push from US mayors to stick to the emissions cuts Washington had pledged to hit, a US official said Tuesday.
The mayor of southern US city Atlanta, Kasim Reed, said he wanted to send a signal of "optimism, passion and action" on fighting climate change to mayors worldwide after Trump announced the pullout this month.
"President Trump's disappointing decision to withdraw from the agreement will actually have the opposite effect in terms of execution," Reed told a handful of mayors from Asia, Africa, Europe, South America and North America meeting in Brussels.
"Right now you have a level of collaboration and focus and sharing of best practices that I haven't seen," he said at a gathering chaired by top EU and UN officials.
"What we did not have really was the level of cooperation, passion and intensity until we saw our president's decision to withdraw," Reed said.
Trump caused outrage when he withdrew the United States -- one of the world's largest emitters of greenhouse gases -- from the 2015 accord which is meant to curb rising temperatures driven by human activity.
Trump said the pact, signed by nearly 200 countries, hit the United States with "draconian financial and economic burdens" while competitors got off lightly.
Reed attended a meeting in Miami on Saturday where he said more than 300 US mayors from both the Democratic and Republican parties all pledged to honour the commitments Trump's predecessor Barack Obama signed onto in Paris.
"I can't think of any major (US) city that is absent," he said adding that this "is not a partisan issue".
"I won't go as far as to say we can reach the exact same goals as we could have with national leadership," he told AFP later.
But he said cities can do enough to keep the ball rolling until the arrival of a new US president committed to the Paris agreement.
He cited experts who argue that cities have the capacity to achieve between 35 and 45 percent of emissions reductions without the involvement of national governments.
The Paris agreement calls for keeping average global warming below two degrees Celsius (3.6 degrees Fahrenheit) above pre-industrial levels, and at 1.5 C if possible.
Maros Sefcovic, the European Commission vice president for energy who co-chaired Tuesday's meeting of mayors, said momentum from cities and other players was "stronger than ever before" despite Trump's decision.
Former New York mayor and billionaire philanthropist Michael Bloomberg, who will join world mayors in Brussels later Tuesday, announced a $200 million plan Monday aiming to back inventive policies in American cities.