U.S. Immigration and Customs Enforcement (ICE) agents will begin knocking on doors and arresting illegal immigrants in pre-dawn raids on Sunday.

ICE has targeted 2040 migrant families in 10 major cities across the United States.

ICE raids will begin before dawn on Sunday in cities including Miami, Atlanta, Chicago, Baltimore, Denver, Houston, L.A., New Orleans, NYC, and San Francisco, said officials who spoke to MSN News on condition of anonymity.

President Donald Trump announced the upcoming raids in a tweet on Monday night, saying U.S. immigration agents will remove “millions” of illegal aliens.

“Next week ICE will begin the process of removing the millions of illegal aliens who have illicitly found their way into the United States. They will be removed as fast as they come in,” Trump tweeted.

Officials say ICE agents will begin rounding up and arresting illegal immigrants who defied deportation orders or failed to show up for deportation hearings.

Acting DHS secretary Kevin McAleenan expressed concerns that rounding up immigrants in their homes and at work would risk separating children from their parents.

Acting ICE director Mark Morgan told ABC News, “This is not about fear. No one is instilling fear in anyone. This is about the rule of law and maintaining the integrity of the system.”

Morgan issued warnings to individuals in Guatemala, Honduras and El Salvador. “Do not come. Do not risk it,” he said.

He added: “Once you receive due process and get a final order, you will be removed.”

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