Washington, Feb 1 (IANS): San Francisco became the first city in the US to file a lawsuit over President Donald Trump's executive order targeting sanctuary cities, the media reported.

"The President's executive order is not only unconstitutional, it's un-American," said Dennis Herrera, the city attorney.

"This country was founded on the principle that the federal government cannot force state and local governments to do its job for it, like carrying out immigration policy. I am defending that bedrock American principle," Herrera was quoted by CNN as saying.

Trump signed an order on January 25 mandating that the federal government withhold grants from localities that limit cooperation with federal immigration enforcement, a practice known as "sanctuary".

The suit sought to prevent the federal government from blocking funds to San Francisco. Herrera estimated that the city had about $1.2 billion in federal funding at stake.

The order also directed the attorney general to explore "appropriate enforcement action" against local government agencies following sanctuary policies.

San Francisco's lawsuit alleged the executive order was unconstitutional and exceeds the President's power. It claimed the city already complies with applicable federal law, according to the report.

The lawsuit stated that Trump's order deprives San Francisco of its sovereign power to choose how it devotes resources and forces it to carry out the agenda of the federal government.

Mayors of several sanctuary cities, including San Francisco, New York and Los Angeles, have vowed to fight the order, saying it will unravel delicate relationships between immigrant communities and law enforcement and tear apart families.

"San Francisco is safer when all people, including undocumented immigrants, feel safe reporting crimes," the lawsuit said.