People converged around the Washington Monument in the US capital to demand a full and independent investigation of the allegations that Trump or his aides might have colluded with Russia

Sharp political passions over President Donald Trump's withdrawal from the Paris climate accord and his links to Russia brought people onto the streets of cities around the globe on Saturday, mostly to condemn but some to praise him.

They came as Nikki Haley, the US ambassador to the United Nations, ended days of confusion to make clear that "President Trump believes the climate is changing" and that man-made pollutants are partly responsible.

She insisted in a CNN interview that Trump, who has often called global warming a "hoax," was concerned about the changing climate. "Just because the US got out of a club doesn't mean we aren't going to care about the environment," she said.

But Trump's decision Thursday to pull out of the Paris treaty, which is designed to cut harmful emissions and slow the Earth's warming, sparked a wave of global condemnation and helped fuel some of the many protest marches on Saturday.

The largest of the many US rallies organized as a March for Truth appeared to be in New York, where as many as 3,000 anti-Trump protesters descended on Foley Square in Lower Manhattan, with some shouting "Liar!" or "Lock him up!" or "Take back America!"

Nearly as many people converged around the Washington Monument in the US capital to similarly demand a full and independent investigation of the allegations that Trump or his aides might have colluded with Russia ahead of last year's US presidential election to help Trump win.

- To 'raise our voices' -

"The president works for the American people, and not for a foreign entity around the world," said Linda Sarsour, an organizer of the march and a co-chair of the Women's March on Washington in January.

People hold signs at the March for Truth on June 3, 2017 in New York

Added Savannah Stark, a 22-year-old from Ohio, "We need to keep working hard and raise our voices until he's impeached."

Other rallies were held in cities from Portland, Oregon on the US West Coast to Munich, Germany and Lima, Peru. Demonstrators also demanded that Trump release his tax returns, a tradition among US presidents which Trump has steadfastly refused to follow.

The US demonstrations appeared to be mostly peaceful. They were far smaller than some of the earlier anti-Trump protests.

They took place just days before the highly anticipated appearance June 8 before a Senate committee of James Comey, who as FBI director was leading an investigation of the Russia matter before Trump fired him early in May.

Trump has denied placing pressure on Comey or the FBI, as well as denying any collusion with Russia.

Trump supporters in a rally Sunday backing his decision to withdraw from the Paris climate treaty

Former FBI chief Robert Mueller has been named as a special counsel to investigate any links between Russia and the Trump campaign.

"We want to get to the bottom of this," Leon Chen, a 32-year-old Texan and self-described Republican taking part in the Washington march, told AFP. "It's not only Russia, it's also his business ties, how him and his family are profiting from this presidency."

- Treaty 'cost us billions' -

At the same time as the other rallies Saturday, a few hundred Trump supporters gathered on the street in front of the White House to applaud the president's withdrawal from the Paris treaty -- a move criticized around the world -- and to demonstrate their backing for the Republican president.

That rally was dubbed "Pittsburgh, Not Paris" -- a reference to the president's statement Thursday, in announcing his plan to withdraw from the international climate treaty, that "I was elected to represent the citizens of Pittsburgh, not Paris."

The Trump supporters included Vince Harrison, 56, a burly retired firefighter from Washington, who said it was his first rally ever.

"I believe in clean air, and I think Americans will still lead on clean air," he said. But he added that the treaty "was costing us billions to be in it while other countries were not required to do anything."

Treaty supporters note that it is actually non-binding -- no country was required to do anything -- but the presence of the United States, the second-largest polluter after China, was considered vital.

Demonstrators take part in the March for Truth rally on the National Mall in Washington, DC, on June 3, 2017

Several people at the pro-Trump rally said they were unconcerned that exiting the treaty would leave the United States in the company of the only two countries that are not signatories: Nicaragua and Syria. And some said other issues mattered more to them than the climate pact -- starting with building a wall on the Mexican border.

A sign at a nearby rally held as a counter to the "Pittsburgh, Not Paris" rally correctly noted that "Pittsburgh's Mayor Supports the Paris Accord."

In fact, Mayor Bill Peduto on Friday joined the mayors of some 175 other US cities and the governors of several states in announcing that his city would follow the terms of the Paris treaty.

Pittsburgh, once known not just as a powerhouse steel producer but as one of the most polluted cities in the country, will work to convert its city vehicle fleet to hybrid and electric vehicles and to make its buildings more energy-efficient, said Peduto.

He was to address a pro-Paris rally Saturday in Pittsburgh.