Mexico City (AFP) - Mexico's government is warning its citizens to "take precautions" amid the "new reality" in the United States, after an undocumented mother was deported to her home country.

Guadalupe Garcia de Rayos was sent back to Mexico on Thursday, a day after she checked in for a routine visit at the US Immigration and Customs Enforcement in Phoenix, Arizona.

A 35-year-old mother of two US-born children, her deportation sparked protests outside the immigration office, according to US media.

"The case of Mrs Garcia de Rayos highlights the new reality that the Mexican community is experiencing in US territory with the stricter application of migration control measures," the Mexican foreign ministry said in a statement late Thursday.

"For this reason, the entire Mexican community is invited to take precautions and keep contact with its closest consulates to receive the necessary help to face this type of situation."

US President Donald Trump signed executive orders last month to build a wall along the US-Mexico border and speed up the removal of immigrants living illegally in the country.

Mexican President Enrique Pena Nieto canceled a White House visit over Trump's insistence that his country will pay for the wall.

Pena Nieto also pledged $50 million to his country's consulates in the United States to increase legal assistance to Mexicans living in the northern neighbor.

The foreign ministry's statement said the consulates have "intensified their work to protect fellow nationals in anticipation the tightening of migration measures by authorities of this (US) country, as well as possible violations to constitutional precepts during such operations or absence of due process."