JERUSALEM — Israeli Prime Minister Benjamin Netanyahu, in his first public comment on a spy affair involving the alleged prison suicide of an Israeli-Australian Mossad agent, defended his country’s intelligence services.

“Israel’s security and intelligence forces operate under the complete supervision of legal authorities which are completely independent,” Netanyahu said Sunday at a weekly Cabinet meeting in Jerusalem.

An Australia Broadcasting Corp. report last week alleged that an Australian citizen living in Israel and working for the Mossad intelligence agency had hanged himself after being imprisoned in 2010. ABC said its probe linked a man named Ben Zygier, also known as Ben Alon, to a figure dubbed “Prisoner X” described in a 2010 report by the Ynet news website as being held under tight security in Israel’s Ayalon prison.

Following the ABC report, top editors of Israeli media outlets were called into Netanyahu’s office and told that all reports relating to the story were subject to security censorship. An Israeli court later allowed a partial lifting of the gag order, and confirmed some of the facts in the ABC report.

“The Prison Service detained a prisoner who held both Israeli and foreign citizenship. For security reasons, the prisoner was held under an alias,” the Justice Ministry said in an e-mailed statement on Feb. 13. “The prisoner was found dead in his cell approximately two years ago.”

Netanyahu said that while Israeli preserved democratic rights and freedom of expression as well as any country, it also had to “safeguard the orderly operations of our security arms. Therefore I request from all of you, let the security forces continue to work quietly,” he said.

The affair has strained relations between Israel and Australia, which was told about Zygier’s arrest 10 months before he was found hanged in his cell, Foreign Minister Bob Carr said last week. On Dec. 16, 2010, Australia was informed through “intelligence channels” that Zygier had died the previous day, Carr said.

The Brisbane Times reported that unidentified Australian security officials suspect that prior to his arrest, Zygier may have been about to expose Israeli use of Australian passports for espionage purposes. The officials said their government was informed of his arrest just after Dubai police announced that Australian passports were used by three of the suspects in the alleged Mossad killing a month earlier of Hamas operative Mahmoud al-Mabhouh.

In May, 2010, Australia expelled an Israeli diplomat to protest what it said was the “involvement of state intelligence” in fake passports linked to the killing of Mabhouh. Israel has never said whether it was involved in the assassination.