Phoenix: An idea floated by US President Donald Trump to send immigrants from the border to "sanctuary cities" to exact revenge on Democratic foes could end up doing the migrants a favour by placing them in locations that make it easier to put down roots and stay in the country.

The plan would put thousands of immigrants in cities that are not only welcoming to them, but also more likely to rebuff federal officials carrying out deportation orders. Many of these locations have more resources to help immigrants make their legal cases to stay in the United States than smaller cities, with some of the nation's biggest immigration advocacy groups based in places like San Francisco, New York City and Chicago.