Actor Peter Fonda has apologised to the family of President Donald Trump for a "vulgar" tweet about his youngest son.
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Fonda's tweet, which was soon delete, said Barron Trump should be ripped from his mother Melania Trump's arms and "put in a cage with paedophiles".
Fonda is one of a number of celebrities expressing his anger and frustration in response to Trump's "zero tolerance" child separation immigration policy.
First lady Melania Trump had the Secret Service informed about the tweet, according to her spokesperson Stephanie Grisham.
However, Fonda eventually deleted the tweet, and released a statement about his regret on Wednesday (local time).
"I tweeted something highly inappropriate and vulgar about the president and his family in response to the devastating images I was seeing on television.
"It was wrong and I should not have done it. I immediately regretted it and sincerely apologise to the family for what I said and any hurt my words have caused."
Barron's older brother Donald Trump Jr tweeted that there was "a special place in hell" for Fonda.
"I didn't think it was possible but Peter Fonda found a way to be as disgusting as his sister Jane was when she stood with the enemy in Vietnam," he wrote.
Fonda, 78, is an Oscar-nominated actor as well as the son of Henry Fonda and younger brother of Jane Fonda. He and his sister have both been vocal critics of the Trump administration.
On Wednesday (local time) Trump signed an executive order reversing the migrant separation policy. However, migrant families will still be detained at the border - just together, instead of separated.
The new order also states that families will be detained for an indefinite amount of time.