The US Justice Department directed federal prosecutors "to identify state and local laws, policies, and activities" that attempt to impede immigration enforcement, according to a report Wednesday.
The Washington Post said a memo by Acting Attorney General Emi Bove instructed federal prosecutors to investigate and potentially take legal action against officials who resist or obstruct immigration enforcement efforts
"Laws and actions that threaten to impede Executive Branch immigration initiatives, including by prohibiting disclosures of information to federal authorities engaged in immigration-enforcement activities, threaten public safety and national security," it said.
Bove directed prosecutors to "identify state and local laws, policies, and activities that are inconsistent with Executive Branch immigration initiatives and, where appropriate, to take legal action to challenge such laws."
The memo specifies that any decision not to press charges against those accused of defying immigration enforcement will need to be urgently reported to the Justice Department for further review.
The move follows executive orders signed by President Donald Trump, declaring a national emergency at the southern US border that paved the way to deploy American troops there.
"All illegal entry (to the US) will immediately be halted," said Trump. "We will reinstate my 'Remain in Mexico'" policy to "repel the disastrous invasion" of the country, he added.
