A mother whose son is being held hostage by Hamas in Gaza has accused Israel's government of “a cynical deception operation that is taken from dark regimes”, after it emerged a government spokesperson had been arrested for allegedly leaking documents that may have undermined a ceasefire and hostage release deal.

It came after a court in Rishon LeZion said Eli Feldstein and three others were under investigation for feeding stories to European newspapers.

Israel Defense Forces (IDF) Radio also reported a fifth arrest in connection with the probe, said to be a major in the military's intelligence branch information security department, tasked with preventing and investigating leaks. The Haaretz newspaper said all unnamed suspects were from this unit.

Prime Minister Benjamin Netanyahu has denied wrongdoing by his staff, but opposition figures and hostages' families have accused his government of sabotaging negotiations.

The stories, given to Britain’s Jewish Chronicle and Germany’s tabloid Bild, were based on partial or false information and came at a crucial time for hostage negotiations.

Speaking at a protest in Tel Aviv, Einav Zangauker, whose son Matan has been held by Hamas for over a year, said the stories “supported Netanyahu’s propaganda lies to torpedo the deal".

The documents claimed Hamas was planning to smuggle Israeli hostages to Egypt - intent on scuppering any proposed ceasefire deal.

Some commentators say the revelations were politically useful for Netanyahu’s hardline position on the talks, which have made almost no progress.

Over 100 hostages out of 251 taken by Hamas on 7 October 2023 remain unaccounted for.

After the stories were published in September, the IDF launched an inquiry to discover the source of the leaks.

This eventually led to the arrest of Eli Feldstein, along with the three others, whose identities have not been revealed.

Mr Feldstein had been working as a government spokesperson and was often seen accompanying the prime minister on visits. He had previously worked for the far-right Minister of National Security, Itamar Ben-Gvir, and before that he served as an IDF spokesperson.

Following news of his arrest, two leading opposition politicians held a news conference.

Benny Gantz, who until recently was in Netanyahu’s war cabinet, said that if sensitive security information was used for a "political survival campaign”, it would not only be a criminal offence, but "a crime against the nation".

Speaking at the same event, the leader of the opposition, Yair Lapid, said that if the prime minister knew about the leaks, "he is complicit in one of the most serious security offences” and that if he didn’t know, he is not fit for office.