US President Joe Biden on Tuesday signed off on an executive order to "gain control" of the southern border with Mexico, as he looks to present a tougher stance on immigration ahead of November's US election.

The long-expected sweeping measures include a temporary closure of the border whenever arrests of illegal migrants by US Border Patrol exceed 2,500 per day.

Given current figures, the measure will therefore come into immediate effect as of Wednesday and will remain in place until the number of apprehensions drops back to below 1,500 per day.

The executive order also facilitates a swifter deportation of illegal migrants back to Mexico.

Unaccompanied minors are not expected to be covered by the new rules and migrants will still be able to request an appointment to present their asylum application under the planned measure, according to the broadcaster CNN.

Biden: 'Necessary steps to secure our border'

"I've come here today to do what the Republicans in Congress refuse to do: take the necessary steps to secure our border," Biden said in a brief address at the White House, flanked by officials from border states.

Under Biden, illegal crossings of the 1,900-mile border have surged to record levels, peaking at an average of 10,000 per day in December.

The numbers have fallen considerably in recent months – a change US officials have attributed to increased enforcement on Mexico's side of the border – but polls show that illegal migration is still one of Biden's biggest obstacles as he seeks reelection.

Criticism from all sides

Biden has come under fire from all sides for his response.

While the UN refugee agency has said it was "profoundly concerned" and other rights groups have threatened legal action over the stringent measures, Republicans such as House Speaker Mike Johnson have dismissed the move as "window dressing."

Former President and likely Republican candidate Donald Trump accused Biden of having "surrendered" the border to illegal immigration, writing on his "Truth" social media platform:

"Millions of people have poured into our country and now, after nearly four years of his failed, weak leadership, pathetic leadership, crooked Joe Biden is pretending to finally do something about the border."

Trump's own attempts to curb illegal migration during his presidency, including a headline-grabbing wall, also failed to tackle the issue.

Biden hit back by slamming Trump and the Republicans for "weaponizing" migration by blocking his request for billions of dollars in border funding in what he called an "extremely cynical, political move."

Addressing the criticism from the left, the 81-year-old said he would not "demonize" migrants and said: "For those who say the steps I've taken are too strict, I say to you: be patient."

In the Senate, Biden has backed a bill written by a combination of Democrat and Republican lawmakers aimed at blocking asylum-seeker applications if the number of irregular crossings reaches a certain level.

Biden's new policy could put pressure on Mexico's Claudia Sheinbaum, who was elected president on Sunday and is set to take office in October, to continue to enhance border enforcement.

mf/jsi (Reuters, dpa)