The Black Lives Matter mural on Manhattan's Fifth Avenue in front of Trump Tower was defaced Monday but quickly fixed, authorities said.
"To whoever vandalized our mural on 5th Avenue: nice try. @NYC_DOT has already fixed it," Mayor Bill de Blasio tweeted, referring to the city Department of Transportation.
The Black Lives Matter "movement is more than words, and it can’t be undone," de Blasio said.
Video showed someone splashing red paint on the mural, which was installed Thursday.
The New York City Police Department said they received a call around 12:15 p.m. Monday about criminal mischief at 725 Fifth Avenue.
"Upon arrival, they discovered that an unknown individual threw red paint on the Black Lives Matter street art," the NYPD said. "There are no arrests, and the investigation is ongoing."
Video obtained by NBC New York showed a man put down a paint can and run off.
After plans for the mural were announced, President Donald Trump called it a "symbol of hate." The president tweeted at the time that it would be "denigrating" to what he called a luxury avenue.
Black Lives Matter murals have been painted in streets in cities across the country after protests over racial inequality and calls for police reform following the death of George Floyd in Minneapolis on May 25.
Floyd, who is Black, died after a white police officer kneeled on his neck as he said he could not breathe. That officer and three others have been fired by the Minneapolis Police Department and been charged.
Last week in the San Francisco-area city of Martinez, prosecutors charged two people accused of defacing a street mural on July 4 with a hate crime.
This article was originally published on NBCNews.com.