The Biden administration will begin reuniting children separated from the parents under former President Donald Trump, the Department of Homeland Security (DHS) announced on Monday.

In all, four families are being reunited this week after they were separated under Trump's "zero tolerance" policy, which was geared at deterring immigration using methods decried by rights groups as inhumane.

US President Joe Biden signed an order in February to form a task force mandated with identifying children who had been separated from their parents at the US-Mexico border during the former administration, and it has spent the past three months compiling a database of hundreds of separated families.

"Many more" reunifications will take place in the coming weeks, the department said in a statement.

“The Family Reunification Task Force has been working day and night, across the federal government and with counsel for the families and our foreign partners, to address the prior administration’s cruel separation of children from their parents,” said DHS Secretary Alejandro Mayorkas said.

“Today is just the beginning. We are reuniting the first group of families, many more will follow, and we recognize the importance of providing these families with the stability and resources they need to heal,” he added.

Speaking during an interview with the CBS television program This Morning, Mayorkas said the department has "hundreds of families" waiting to be reunited, vowing all of them will be./aa