NEW YORK -- Attorneys general from 18 US states sued on Tuesday to block President Donald Trump's move to end a decades-old immigration policy known as "birthright citizenship" guaranteeing that US-born children are citizens regardless of their parents' status.

The 18 states joining the lawsuit to stop the order are New Jersey, California, Massachusetts, Colorado, Connecticut, Delaware, Hawaii, Maine, Maryland, Michigan, Minnesota, Nevada, New Mexico, New York, North Carolina, Rhode Island, Vermont, and Wisconsin, plus two cities: the District of Columbia and San Francisco.

"Trump's roughly 700-word executive order, issued late Monday, amounts to a fulfillment of something he's talked about during the presidential campaign," reported The Associated Press about the development. "But whether it succeeds is far from certain amid what is likely to be a lengthy legal battle over the president's immigration policies."

Birthright citizenship means anyone born in the United States is a citizen, regardless of their parents' immigration status. People, for instance, in the United States on a tourist or other visa or in the country illegally can become the parents of a citizen if their child is born here.