Lena Dunham and Amber Heard among actresses protesting at US-Mexico border against Trump’s policy of splitting migrant families

Celebrities gathered at the border between the United States and Mexico to protest against the separation of migrant children from their parents.

Stars including Amber Heard, Lena Dunham, Sia and Mira Sorvino travelled to the town of Tornillo in Texas to call for an end to the policy. Donald Trump has faced intense criticism for the practice of separating families, which stems from a zero-tolerance approach that criminally charges anyone caught crossing the border illegally.

More than 2,300 children were separated from their parents in May and June. They are being held in detention centres, with pictures and audio emerging of them sleeping in fenced enclosures and crying. Babies and toddlers have been taken to facilities called “tender age shelters” in southern Texas.

At yesterday’s protest in Tornillo, which hosts a facility housing migrant children, Heard posted a shot of herself with a placard reading: “Apartheid was legal. Holocaust was legal. Legality is a matter of power, not justice.” She captioned it: “Law is meant to protect and defend justice, not destroy it.”

Sorvino posted a selfie alongside Dunham, writing: “TY so much lenadunham for inviting me on this moving journey of bearing witness at the border ... knowing that those children were there on the other side of the barbed wires, in a desert where the heat was easily over 100, made me want to fight even harder to #EndFamilySeparation.”

Dunham posted a shot of protesters and wrote: “We came to Tornillo, Texas, to show our solidarity with the families who have been separated, the children who are alone, the parents who are grieving and the undocumented Americans who are losing more than I can fathom. Thank you, Tornillo, for showing us a warm border welcome and reminding us that together we rise.”

Last week, facing a backlash, Mr Trump signed an executive order he claimed would keep families together. But it does not address the problem of families already separated.