The US government has abandoned negotiations to financially compensate migrant families separated at the southern border with Mexico during the "zero tolerance" policy of former president Donald Trump, representatives of both parties said Thursday.

The administration of President Joe Biden said no agreement had been reached with attorneys for the families who filed lawsuits over the separations, but left open the possibility of doing so in the future.

"While the parties have been unable to reach a global settlement agreement at this time, we remain committed to engaging with the plaintiffs and to bringing justice to the victims of this abhorrent policy," the Justice Department said in a statement.

The plaintiffs, who are seeking compensation for the psychological damage the separations caused them, announced that they will continue with their legal battle.

"We are going back to court," said Lee Gelernt, deputy director of the American Civil Liberties Union's Immigrants' Rights Project.

"The trauma inflicted on these children and parents at the hands of our very own government is unfathomable. We need to do the right thing," he told AFP.

"It would be an understatement to say we are disappointed that the Biden administration allowed politics to get in the way of helping the little children deliberately abused by our government," he said.

Children take part in a protest against US immigration policies outside the US embassy in Mexico City on June 26, 2018
Children take part in a protest against US immigration policies outside the US embassy in Mexico City on June 26, 2018 AFP / RODRIGO ARANGUA

After taking office in January on the promise of a more "humane" approach to immigration, Biden officially rescinded Trump's zero tolerance policy on the southern border.

That directive, which the former Republican president had suspended in June 2018 due to a massive public backlash, prioritized criminal prosecutions of people caught illegally entering the country, leading to the separation of thousands of minors from their parents.

In late October, the Wall Street Journal reported that the departments of justice and homeland security were negotiating compensation with affected families who had sued the government.

The paper said the payments could be as high as $450,000. Biden dismissed that figure in November but said he supported compensation for separated migrant families.

The Department of Homeland Security (DHS) said in June that it had identified 3,913 children separated from their families at the US-Mexico border during the Trump administration.

Of these 1,786 minors had been returned to their families, while the task force created by Biden to advance reunifications continues in its work.

However, court documents state that 5,500 children were separated from their migrant parents.

The arrests of undocumented migrants on the southern border of the United States reached record numbers in recent years, the majority coming from Central America and Mexico.