Hassan Ghani, 26, from Glasgow, was detained by the Israeli navy on Thursday when a protest boat bound for Gaza was seized.
The TV journalist was aboard one of two vessels trying to break Israel’s blockade of the Palestinian territory. They were towed to Ashdod.
Mr Ghani was also part of a Gaza aid flotilla stormed by Israeli commandos last year, leaving nine people dead. The latest incident is not thought to have resulted in casualties.
Mr Ghani’s family spent Eid yesterday uncertain about when they would see him again.
The Foreign Office had originally told the Ghani family he would be released within 72 hours, but after he refused to sign a document saying he had entered Israel illegally he could be in custody until at least Wednesday.
His father Haq said yesterday: “Today is Eid, and it is terrible that we have no real contact with our son.
“It is extremely worrying that he was seized in international waters – or kidnapped, I’d say – then forcibly taken into a country he had no intention of going to.”