Migrants who cross the southern US border illegally will no longer be eligible for asylum under a new rule, the Trump administration has said.

The new measures would deny asylum to those who breach any presidential restriction on entry.

The president can stop migration in the "national interest", a statement said. Rights groups have called the move "illegal."

Immigration was a major focus in Mr Trump's mid-term election campaign.

Before the mid-terms, President Trump frequently denounced a caravan of thousands of Central Americans making their way north through Mexico.

He ordered troops to the border and declared the migrants to be an "invasion". Without offering evidence, Mr Trump repeatedly suggested the caravan was politically motivated.

Acting Attorney General Matthew Whitaker and Homeland Security chief Kirstjen Nielsen announced what is known as the Interim Final Rule on Thursday.

The joint statement said presidents have the power to "suspend the entry of all aliens" and to impose "any restrictions he may deem to be appropriate on them" if they are judged to be "detrimental" to US interests under the Immigration and Nationality Act. (BBC)