The city of Tulsa said it would resume on Monday excavation work meant to find mass graves that were dug after white mobs attacked Black residents of the city in 1921 in one of the worst incidents of racial violence in U.S. history.

The city announced in a press release that workers would resume operations on a "test excavation" in a section of the city's Oaklawn Cemetery that has been identified as possibly containing a mass grave. Operations were put on hold in March due to concerns related to the coronavirus pandemic.

The city is working with the University of Oklahoma on the effort. 

“As we resume with the test excavation, we’re taking all precautions to do so under the safest environment possible. I’m thankful for the health and wellbeing of our partners who have diligently coordinated with our team to move forward with this work during the constraints of the pandemic and record heat we are expecting," Mayor G.T. Barnum said in a statement accompanying the release announcing that the world would continue.

The 1921 riot, which targeted residents of the Tulsa area known then as "Black Wall Street" due to a high concentration of Black-owned businesses, resulted in hundreds of deaths and the destruction of much of the district in fires, with the full extent of the damage being unknown to this day. The massacre was recently featured as an event on the widely-viewed HBO series "Watchmen," prompting new calls for it to be studied.

“For decades, Oklahoma schools did not talk about it. In fact, newspapers didn’t even print any information about the Tulsa Race Riot. It was completely ignored. It was one of those horrible events that everyone wanted to just sweep under the rug and ignore,” Sen. James Lankford (R-Okla.) told a local news outlet earlier this year.

The excavation will result in the cemetery being temporarily closed to the public, according to the release. City officials are searching for mass graves dug after the 1921 massacre in which dozens or even hundreds of the city's Black residents could be interred.