President Joe Biden has issued sweeping new executive actions aimed at curbing record migrant arrivals at the US-Mexico border that have left him politically vulnerable in an election year.

Under the new actions, officials can quickly remove migrants entering the US illegally without processing their asylum requests.

That will happen once a daily threshold is met and the border is "overwhelmed", the White House said in a statement.

The US also unveiled new actions aimed at speeding up cases and easing pressure on overburdened US immigration courts.

Mr Biden spoke about the order at an event on Tuesday afternoon with several border town mayors. He said "this action will help us gain control of our border".

Some immigration activists already have criticised the move, however.

"It’s unfortunate that politics are driving the immigration conversation in an increasingly restrictive direction," said Jennie Murray, president and the CEO of the National Immigration Forum.

In his speech, the president criticised Republicans for not passing bipartisan immigration reform earlier this year - and he asked progressive critics of the new executive action to "be patient".

"We're wearing thin right now. Doing nothing is not an option."

More than 6.4 million migrants have been stopped crossing into the US illegally during Joe Biden's administration.

Migrant arrivals have plummeted this year, though experts believe that trend is unlikely to continue.