US border wall
© Mike Blake / Reuters
It's not just the US-Mexico border which could witness a forbidding wall cropping up soon. A GOP representative wants to build a similar barrier between Arizona and its immigrant-friendly neighbor California.

Rep. Martha McSally (R-Ariz.) proposed erecting a border wall between California and Arizona to protect Arizona from "dangerous criminals" who, she claims, are protected by California's sanctuary cities policy. McSally made the remarks during a round-table discussion about sanctuary cities on Tuesday at the White House.

In Arizona, "we often look into the dangers of the southern border. But if these dangerous policies continue out of California, we might need to build a wall between California and Arizona as well, to keep these dangerous criminals out of our state," she said.

The lawmaker, who is running this year to be Arizona's Senator, is concerned that the effects of sanctuary cities extend beyond California alone. The Golden State cannot "provide sanctuary for these criminals and think that it's only impacting California dangerously," she warned.

'Sanctuary cities', are municipalities which have adopted policies against cooperating with federal immigration officers in detaining illegal immigrants. Trump has frequently railed against sanctuary cities, arguing that they put US citizens at risk from "criminal aliens".

Last week, while surveying prototypes of his proposed US-Mexico border wall in San Diego, Trump took the opportunity to criticise California's stance on immigration. "The place is totally out of control. You have sanctuary cities, where they have criminals living in the sanctuary cities. And then the mayor of Oakland goes out an notifies when ICE is going in to pick them up," he said.