The US Senate has rejected a bipartisan proposal protecting so-called "dreamers", leaving in limbo the future of one-point-eight million young adults brought to the US illegally as children.

Senators on Thursday failed to get the 60 votes necessary for a bill to advance. The bill was crafted by moderate Republicans and Democrats billing themselves as the "Common Sense Coalition". Dreamers are currently under the protection of the Deferred Action for Childhood Arrivals program, which is due to start expiring next month. Lawmakers are trying to replace it with new bills that guarantee the group's rights. But President Trump has insisted any immigration bill to protect Dreamers should also include funds to build a border wall with Mexico, ending the visa lottery program, and imposing curbs on visas for relatives of legal immigrants.