Opponents of the U.S. President Donald Trump are holding marches in 135 cities across the country over Russia's alleged role in the presidential campaign.
Organizers of Saturday's 'March for Truth' want an independent commission to investigate the claims.
Groups taking part include MoveOn and the Working Families Party, as well as campaigners such as Swing Left, Flippable, and the TownHall project.
They're hoping to repeat the success of the Women's March which saw millions of people take to the streets after Trump's inauguration.
“There are crucial unanswered questions about the relationship between the Russian state and Donald Trump, his associates and his campaign” reads a message on the March for Truth website.
The former FBI Director Robert Mueller has been installed as special counsel for the official investigation.
But activists are calling for an independent body similar to the 9/11 commission.
Sean Eldridge, a former New York congressional candidate and founder of Stand Up America, is one of those sponsoring the rallies.
He told NBC "Donald Trump and Republicans in Congress need to know that we won't let this issue get swept under the rug, and that's why thousands of Americans across the country will be marching to demand the truth".
Hundreds of people have been taking to the streets in lower Manhattan.
People gathered in Foley Square and listened to speakers.
Javier Munoz, who plays the lead in Broadway's "Hamilton," sang a patriotic song compilation.
Some of the crowd carried banners saying "Alternative Facts Are Lies," "Facts Matter" and "Save Our Country."