The mayor of California's largest city, Oakland, who had earlier this year warned immigrants about a government raid, has defended her move as a “duty” to protect her residents when they  are “unjustly attacked” under the Trump administration's “racist lie.”

Back in March, Mayor Libby Schaaf posted a message on Twitter, saying that she had learned from “multiple credible sources” that Immigration and Customs Enforcement (ICE) “is preparing to conduct an operation in city.

Immigration and Customs Enforcement, which planned to target around 1,000 immigrants living illegally in the Bay Area city in March, said the warning prevented the arrest of as many as 800 people.

President Donald Trump, who was irked by the move, called on his attorney general, Jeff Sessions, to prosecute her for “obstruction of justice.” He said the  mayor “informed them, and they all fled—or most of them fled—and that whole operation, that took a long time to put together.”

In his March announcement of a lawsuit against Schaaf, Sessions accused her of being responsible for “800 wanted criminals” being “at large.’ The mayor, however, defended her move in an article to The Washington Post, saying, “ I am not obstructing justice. I am seeking it.”

“As mayor, it’s my duty to protect my residents — especially when our most vulnerable are unjustly attacked. As a leader, it’s my duty to call out this administration’s anti-immigrant fearmongering for what it is: a racist lie,”she wrote.

In the article, she argued that the US immigration system is broken. She also claimed that according to studies, undocumented immigrants commit crimes at lower rates than those of American citizens.

Oakland, and other diverse communities like it, have seen a drop in crime rates, she wrote.

The Trump administration has taken a tougher stance on immigration from Latin America, most notably with moves to expel hundreds of thousands of immigrants from Mexico, Honduras, Nicaragua, Haiti and El Salvador. Trump has also imposed a ban on Muslims entry into the US.