Mexico is launching a smartphone app that allows Mexican migrants to warn relatives and instantly alert the nearest consulate if U.S. immigration agents detain them, officials said Friday.

Why it matters: The announcement came as part of a broad warning from the administration of Mexico's President Claudia Sheinbaum that the nation will defend the human rights of Mexican citizens in the U.S. amid President-elect Trump's mass deportation plans.

Zoom in: Mexico Foreign Secretary Juan Ramón de la Fuente said at a press conference that the "emergency notification" app will go live in January.

• "I have personally attended several open meetings where the key message is to tell our fellow citizens that they are not alone and will not be alone," De la Fuente said.

Zoom out: De la Fuente said Mexico's "Know Your Rights" program will be part of a rapid response to possible enforcement scenarios or "other intimidating actions."

• Mexico's legal protection program includes 329 legal advisors at all 53 consulates in the U.S., along with voluntary support from consultants and law firms across the country, he said.

State of play: Trump has said his mass deportation plan will likely include U.S. citizens who are the children of undocumented immigrants and the erection of new detention camps around the country.

• More than two dozen Republican governors also said that they'll use "state law enforcement or the National Guard" to help with mass deportation, raising alarm from advocacy groups.

The intrigue: Mexico is encouraging all Mexican citizens with children born in the U.S. to register them with the consulates.

• "Not everyone has done this yet. We strongly encourage everyone to register with our consulates as this enables us to provide legal protection when needed," De la Fuente said.

Reality check: These mass deportations will also likely encounter several procedural roadblocks, and the estimated $150 billion to $350 billion cost of executing them is steep.

• Currently, the U.S. does not have enough holding cells to house millions of people placed in deportation proceedings.

• The American Civil Liberties Union (ACLU) tells Soixa that temporary holding centers will likely be inhumane and poorly built and the group plans on monitoring them.

Flashback: Trump said last month he spoke to Sheinbaum about stopping migration into the U.S.

• Trump said in a Truth Social post that he had "a wonderful conversation" with Sheinbaum, claiming she "agreed to stop Migration through Mexico, and into the United States, effectively closing our Southern Border."

• In a statement, Sheinbaum said she and Trump discussed Mexico's strategy on migration and that she told him Central American caravans are not arriving at the northern border as they're being taken care of in Mexico.

The bottom line: Any mass deportations would entail expelling people into Mexico, which would draw pushback because it'd overwhelm the country's capacity to manage the flow.