New York Mayor Bill de Blasio plans to travel to Hamburg, Germany, on the sidelines of the G-20 summit to speak at a demonstration against President Trump's policies and the spread of populism in Europe.

De Blasio, a Democrat, will deliver the keynote address at a protest event organized by a group called "Hamburg Zeigt Haltung," or Hamburg Shows Attitude, his office announced Thursday afternoon.

The mayor will be "on stage on Saturday on our rally for human rights and democracy as keynote speaker," according to a tweet from the organization.

"It's important that American leaders confront head-on, locally and around the world, the damaging rhetoric and policy stances of the Trump Administration," said Eric Phillips, de Blasio's press secretary. "The mayor will be sharing New York and American values with an international audience that we worry only sees and hears from our President. Sharing our values and aggressively representing New Yorkers at home and abroad helps keep our city's needs and strengths at the forefront of an important discussion."

According to the New York Daily News, supporters of the rally told Norddeutscher Rundfunk, a Hamburg public broadcasting network, they were not protesting the G-20 summit itself, but rather some of its participants, including Trump, Russian President Vladimir Putin, Turkish President Recep Tayyip Erdogan, and Chinese President Xi Jinping.

The G-20 summit has already been marked by protests.

Thousands of protesters clashed with police Thursday.

Video from the scene showed German police in riot gear charging into the crowd of demonstrators, and law enforcement deploying water cannons to disburse the crowds protesting outside of buildings where world leaders will meet for the two-day gathering.

At least 30 demonstrations were announced for before and during the summit.

Police expected roughly 100,000 protesters, according to Reuters.