More Haitian migrants could be released into the United States in coming days, US Homeland Security chief Alejandro Mayorkas said Sunday, after a days-long border crisis which became a major headache for Joe Biden’s administration.

Officials said on Friday that some 12,400 migrants, most of them from Haiti, were released into the United States in recent days, part of a flow of thousands crossing the Rio Grande river from Mexico near Del Rio, Texas.

They will have their cases heard by an immigration judge to determine whether or not they will be allowed to stay.

The migrant number could yet rise, Mayorkas said in a series of appearances on US talk shows.

“It could be even higher,” he told Fox News Sunday.

The situation facing the migrants on the border and in Del Rio in particular has provoked major backlash for the Biden administration.

Since September 9 some 30,000 migrants, most of them Haitian, have turned up in the town.

The number of people, along with controversial images of US border patrol on horseback appearing to threaten the migrants and the decision to deport thousands back to Haiti, ignited widespread fury.

On Friday officials said that the migrants had been dispersed.

In addition to the 12,400 who are being allowed to plead their case before a US judge, around 2,000 people were returned to Haiti on expulsion flights, and an estimated 8,000 have voluntarily returned to Mexico.

Another 5,000 are being processed by the Department of Homeland Security (DHS) to determine if they will be subject to removal proceedings, officials said Friday. It is this 5,000 who could add to the numbers already entering the United States. 

Republicans have seized on the situation to batter the Democratic president, with Senator Tim Scott accusing Biden of failing to secure the border.

“I think President Biden and his administration owns the crisis that they’ve created,” Scott told CBS on Sunday.

Mayorkas, seeking to defuse the crisis, said DHS was following the law to determine whether to deport migrants who cross the border illegally.

But in another interview he deplored those same laws.

“We are working in a completely broken system,” he told NBC Sunday. “I’ve never heard anyone say that the laws in immigration are well structured.”