The United States announced Friday it was lifting a public health order imposed because of the Covid-19 pandemic that required the immediate expulsion of migrants arriving at the border.

Department of Homeland Security Secretary Alejandro Mayorkas said the Centers for Disease Control and Prevention's so-called Title 42 public health order would be lifted next month.

"Title 42 remains in place until May 23 and, until then, DHS will continue to expel single adults and families encountered at the Southwest border," Mayorkas said in a statement. 

Title 42, which was been in place since March 2020, required the expulsion of unauthorized single adults and family units arriving at US land borders, not letting them apply for asylum, in order to protect against the spread of Covid-19.

Mayorkas said more border agents were being deployed to "process new arrivals, evaluate asylum requests, and quickly remove those who do not qualify for protection."

"We will increase personnel and resources as needed and have already redeployed more than 600 law enforcement officers to the border," he said.

Migrant advocates had argued that Title 42 was becoming outdated as the pandemic eased and an affront to international conventions allowing people to claim asylum.

"Once the Title 42 Order is no longer in place, DHS will process individuals encountered at the border pursuant to Title 8, which is the standard procedure we use to place individuals in removal proceedings," Mayorkas said. 

"Nonetheless, we know that smugglers will spread misinformation to take advantage of vulnerable migrants," he said. "Let me be clear: those unable to establish a legal basis to remain in the United States will be removed."

Crossings from Mexico have been surging in recent weeks and Republican lawmakers have warned that immigration has become a "humanitarian disaster."

Border guards caught illegal migrants 1.7 million times in the last fiscal year -- the highest number ever recorded and four times the expulsions posted in Trump's last year in the White House, when numbers were down in part because of the pandemic.

Republicans warned of a greater surge should President Joe Biden end Title 42 and the president's own Democratic Party was divided over the move.

According to advocacy organization Human Rights First, Title 42 expulsions had led to nearly 10,000 reports of kidnap, torture, rape and other violent attacks against people blocked in or sent back to Mexico.

Kennji Kizuka, the group's associate director for refugee protection research, said the reports represented "just a tiny fraction" of the true cost of the "nightmarish policy."