The boat's occupants included children, said IOM, in a post on social media platform X
Assange was arrested on Thursday in London when Ecuador revoked his diplomatic asylum after seven years of being holed up its embassy.
“We expect all the relevant authorities to ensure Mr Assange’s right to a fair trial is upheld by authorities, including in any extradition proceedings that may take place,” UN human rights spokeswoman Ravina Shamdasani told a Geneva news briefing.