The United States on Friday ended a Covid-19 border restriction that had blocked many migrants at the border with Mexico, immediately replacing the order known as Title 42 with a sweeping new asylum regulation meant to deter illegal crossings.

Several last-minute court actions added confusion to how President Joe Biden’s reworked border policies will play out, with advocates filing a legal challenge to the new asylum restrictions as they took effect.

In El Paso, Texas, hundreds of migrants slept outside on American soil in front of the border fence as the sun rose on Friday morning. Texas National Guard, state troopers and border agents patrolled the surrounding area where migrants have waited after surrendering to US border authorities.

Across the border in Ciudad Juarez a day earlier, migrant shelters were half full, holding about 1,600 people. Two shelter directors said many of the migrants were planning to apply for legal US entry via an app called CBP One.

Just before Title 42 was set to expire at midnight on Thursday, immigration advocates represented by the American Civil Liberties Union sued over the new asylum bars, claiming they violate US laws and international agreements.

Advocates argue the new regulation, put in place by Biden’s Democratic administration to curb illegal crossings, resembles restrictions imposed by his Republican predecessor, Donald Trump. The rights groups successfully blocked the Trump rules in court and asked the same California-based federal judge to block these as well.

US Homeland Security Secretary Alejandro Mayorkas defended the Biden regulation in a series of television interviews on Friday morning, saying it aims to encourage migrants to enter using legal pathways rather than crossing illegally

“It’s going to be a tough transition,” he told MSNBC.

In chaotic scenes on Thursday, migrants scrambled to enter the country before Title 42 expired and the new rule went into effect. The regulation presumes most migrants are ineligible for asylum if they passed through other countries without first seeking protection elsewhere, or if they failed to use legal pathways for US entry, which Biden has expanded.

Thousands of migrants have waded through rivers, climbed walls and scrambled up embankments onto US territory in recent days, hoping to be processed before midnight. Some migrants turned themselves in to border officials. Others tried to cross undetected.

In Matamoros, Mexico, on Thursday afternoon groups crossed the Rio Grande River in chin-high water. Some carried tiny babies and bags of belongings above their heads to make it into Brownsville, Texas.

More migrants – including families with young children wrapped in Mylar blankets – awaited processing while penned between two towering border walls in San Diego, California, across from Tijuana, Mexico.

Trump first implemented Title 42 in March 2020 as Covid swept the globe, with US health officials saying it was needed to curb the spread of the virus in detention facilities. The order allowed American authorities to quickly expel migrants to Mexico or other countries without a chance to request US asylum.

But Democrats, public health experts and immigration advocates saw it as an extension of Trump’s quest to block migrants at the border. Biden, who campaigned on reversing Trump’s policies, kept the order in place and ultimately expanded it.

Migrants have been expelled more than 2.7 million times under Title 42, although the total includes many repeat crossers.

Mexico has generally only accepted certain nationalities – its own citizens, migrants from northern Central America and more recently migrants from Venezuela, Cuba, Haiti and Nicaragua. So, during the same period, around 2.8 million migrants ineligible for expulsion were allowed into the United States under a process known as Title 8 to pursue their immigration claims in court, which can take months or years.

Even before Title 42 expired, along with the end of the Covid public health emergency, Biden’s administration was grappling with record numbers of migrants at the US-Mexico border, straining US authorities and border cities.

Republicans fault Biden for easing Trump’s more restrictive policies, while the Biden administration has blamed Republicans for blocking legislation to reform the immigration system. But with the new asylum rule, Homeland Security Secretary Mayorkas and other Biden officials have been trying to spread the message that illegal crossers will face consequences, sending troops and thousands of additional personnel to the borer.

Some migrants were heard on Thursday saying it would be harder to enter the country after May 11 and rushed to cross before the deadline. Daily apprehensions rose above 10,000 this week and detention capacity maxed out.

Due to the high volume of arrivals, agents on Wednesday began releasing some migrants without a notice to appear in immigration court where they can make an asylum claim, telling them to report to an immigration office later. But late Thursday night, a federal judge in Florida blocked such releases, saying they failed to follow proper regulatory procedures.

US Customs and Border Protection called the ruling “harmful” and said it would “result in unsafe overcrowding” at border facilities.

– A Reuters report