Melania Trump is pictured during a meeting with Polish President's wife Agata Kornhauser-Duda (Unseen) at the Belvedere Palace in Warsaw on July 6, 2017. (ANDRZEJ HULIMKA/AFP/Getty Images)

Violent demonstrators at the G20 Summit in Germany prevented first lady Melania Trump from participating in a program for the gathered leaders’ spouses. Instead, she was forced to stay in her guest house in Hamburg until the city's police said it was safe.

"The Hamburg police could not give us clearance to leave," the first lady's spokeswoman Stephanie Grisham said in a statement Friday. "She was prevented from participating in today's spousal program, which she was looking forward to."

The spouses of G20 leaders were scheduled to tour a climate change center in Hamburg and to later take a river cruise while the world leaders attended the summit, according to a report by CNN. The plans were canceled when the first lady said she couldn't attend.

READ: What Melania Trump Wore For 4th Of July At White House

While the first lady's activities were foiled by the protests, she tweeted her concern for those injured by the escalating violence. "Thinking of those hurt in #Hamburg protests. Hope everyone stay safe! #G20" she tweeted Friday.

Hamburg was rocked with another day of violence Friday as protesters clashed with the city's police outside of the summit where world leaders met. During the protests, dozens of cars were set on fire, and in a video, one user on Twitter said that it "looked like war" in the city.

In retaliation, the police utilized water cannons, pepper spray, and batons to disperse marchers. Videos and photographs of the clashes were uploaded to social media.

German Chancellor Angela Merkel condemned the protests Friday during a statement to update reporters on the event.

"Violent demonstrations put lives at risk, they put the people’s own lives at risk, they endanger police officers and residents, so that is not acceptable," she said, thanking authorities for their "hard work" to secure the event.

READ: Why Are There Zombies At G20? Meet The 'Welcome To Hell' Protesters

The first lady was later allowed to leave the guest house where she joined the President at the G20 Summit during his meeting with Russia's Vladamir Putin. The meeting went four times as long as it was supposed to, and according to Secretary of State Rex Tillerson, Melania Trump was sent in to try and get the president and his team out of the meeting, but to no avail.

“Several times, I had to remind the president, people were sticking their heads in the door and I think they even sent in the first lady at one point to see if she could get us out of there, and that didn’t work either,” Tillerson said, according to a report by the New York Post.