The African Burial Ground Monument in New York City was vandalized on Thursday with a racist message suggesting African-Americans should be killed, according to multiple reports.

New York police said the Manhattan monument was defaced with the word "kill" followed by a racial slur written in black marker, The New York Times reported. The message was immediately cleaned off after it was reported.

Police have not yet identified a suspect but the New York Police Department Hate Crime Task Force is looking through security footage, according to NBC New York.

The monument marks a burial ground containing an estimated 15,000 skeletal remains of colonial African-Americans from New York City. Many of those buried were slaves.

The African Burial Ground Monument is considered a sacred site for the country's African-American population, the Times reported. It was established in 2009 and holds the remains of free and enslaved Africans from the 17th and 18th centuries.

The vandalism occurred hours before police responded to reports that a Brooklyn synagogue was defaced with anti-Semitic graffiti hours before "Broad City" star Ilana Glazer was set to hold an event.

Police on Friday arrested 26-year-old James Polite in connection with the synagogue vandalism.

He is being charged with four counts of criminal mischief as a hate crime in connection with graffiti written inside Union Temple, which read "Hitler," "Jews better be ready," "Die Jew rats, we are here!" and "kill all Jews," according to multiple reports.

Polite is also being charged with multiple arson fires at Jewish gathering places, including one at a yeshiva and another at a Jewish banquet hall, according to local ABC affiliate WABC.

Glazer canceled the Thursday "Get Out The Vote" event set to be held in the synagogue after the graffiti was discovered two hours beforehand.

A recent report from California University's Center for the Study of Hate and Extremism found hate crimes have increased in major U.S. cities over the last two years.