The Department of Homeland Security is planning raids targeting undocumented immigrants, according to an NBC report.

It has been described as "the largest operation of its kind in the history of ICE," according to sources familiar with an internal document.

"Operation Mega" is scheduled to take place over five days starting Sept. 17. It is still in the planning stage, NBC reports, and may be changed or canceled.

U.S. Immigration and Customs Enforcement operations targeting undocumented immigrants are not uncommon, but usually have deportation goals in the hundreds or low thousands, NBC reports.

Operation Mega would target 8,400 undocumented immigrants. One official told NBC they would focus on adults who might be gang members and criminals. Agents would not target juveniles, one source told NBC.

The operation could be impacted by the hurricanes in the Atlantic. Agents would not target non-criminal immigrants fleeing Hurricane Irma, Department of Homeland Security spokesperson Dave Lapan told NBC.

NBC REPORT: Homeland Security Plans Massive Roundups of Undocumented Immigrants