Unlicensed immigration consultants, commonly known as notarios in Latin American communities, can cause serious harm to an immigrant's legal case, experts say.
The Houston Police Chief, Art Acevedo said: " I've had kids come up to me at forums with tears in their eyes, they're afraid to go to school, they're afraid to come home and find that their parents have been deported".
The operation will target entire families that have been ordered removed, but some family may be separated if some members are in the country legally.
The president, speaking to reporters at the White House on Friday, said he was not concerned that the advance notice could help targeted immigrants evade arrest.
"If people who ignore court orders & stay in the USA illegally are not deported, we do not have rule of law", the Trump campaign war room said in a message on Twitter.More news: Thousands join Hong Kong protest against Chinese traders
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Immigration and Customs Enforcement reportedly planned to start raids nationwide to enforce deportation orders.
ICE said in a previous statement its focus was arresting people with criminal histories but any immigrant found in violation of USA laws was subject to arrest.
Ken Cuccinelli, acting director of US Citizenship and Immigration Services, said Wednesday that ICE has removal orders for some one million migrants, but added that it has nowhere near the manpower or facilities to arrest and deport that many.
Recounting an exchange with representatives of Hispanic evangelical groups, Pelosi said they told her: "on Sunday, west of the MS, our people are in church".
Trump sent Vice-President Mike Pence to visit some of the criticised detention facilities in McAllen, Texas, on Friday along with journalists, who have generally been denied access to detained immigrants.
"ICE staff in Miramar have apparently gone over to Immokalee and they're basically starting to stage to begin these raids but I don't have any first-hand information", Wasserman Schultz said.
Trump's confirmation of the raids came amid widespread criticism of the overcrowded, unsanitary conditions detained immigrants are allegedly residing in at facilities along the southwestern US border.