The claim: US President Donald Trump has repeated his assertion that he inherited - and ended - a policy from President Obama that separates children from parents who cross the US-Mexico border illegally.

Verdict: The policy was introduced under the Trump administration. He subsequently ended that policy, but some family separations have continued to take place.

The president has frequently blamed his predecessor and the Democrats for a policy that led to children being separated from their parents at the southern US border.

Even though the Trump administration has officially ended the practice, some children are still separated and some are reportedly being kept in appalling conditions.

How did family separations come about?

Under a "zero-tolerance" immigration policy introduced in April 2018, adult undocumented migrants crossing the US-Mexico border were criminally charged and jailed.

These had previously been treated as civil violations.

Image copyright Getty Image caption US Border Patrol agents arrive to detain a group of Central American migrants near the US-Mexico border in June 2018

Because the children of prosecuted migrants were not charged with any crime, they were not permitted to be jailed with their parents, which led to children being placed in shelters or foster care.

In addition to removing children from apprehended illegal migrants, children have also been separated from asylum seekers.

The president signed an executive order in June 2018 reversing the policy, promising to keep families together. A court order then ended separations and required families to be reunited.

Hundreds of children however remained in government shelters, and the New York Times has reported that a further 700 families have been separated in the past year because of "loopholes" in the court order.

This has happened when parents have a criminal conviction or a disease, or when it is an aunt, uncle, or sibling accompanying the child. Some parents may themselves be under 18 - and also detained.

Lawyers were recently granted access to a border facility in Texas where children were being held, and reported seeing horrifying conditions inside.

Children were "locked up in horrific cells where there's an open toilet in the middle of the room" where they ate and slept, one of the lawyers told the BBC.

By law, migrant children are not supposed to be held in customs and border patrol facilities for more than 72 hours. However rights groups say many children are staying there much longer.

Whose policy?

President Trump has blamed Mr Obama and Democrats for the policy.

Last year he called on Democrats to "end the horrible law that separates children (from) their parents once they cross the border in the US".

However, there has been no law that mandates separating children from parents who cross the border illegally.

Image copyright US Customs and Border Protection Image caption This image from the US Customs and Border Protection shows the foil blankets given to children in 2018

Image copyright Twitter

In 1997, Democrat President Bill Clinton signed the Flores Settlement law that required unaccompanied minors who arrive in the US to be released to their parents, a legal guardian or an adult relative.

If no relatives are available then the relevant government agency can appoint an appropriate adult to look after the child.

And in 2008, Republican President George W Bush signed an anti-trafficking statute that requires unaccompanied minors to be transferred out of immigration centres within 72 hours.

Neither of these recommends separating families.

Following the introduction of the "zero tolerance" immigration policy in April 2018, Mr Trump's then Attorney General Jeff Sessions said: "If you don't want your child separated, then don't bring them across the border illegally."

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