Some Israeli government analysts believe Iran already has at least one nuclear bomb, an Israeli journalist wrote in an article published Friday.

Shalom Yerushalmi, writing in the national daily Maariv, said that “government security sources up to date on development in Iran,” told him recently that Tehran has crossed all points of no return and already has its first nuclear weapon, and maybe more.

The report marks the first time a government official has been quoted saying Iran already has a nuclear weapon. No sources in the piece were named.

The information, if true, would mark a major shift in international relations and would be a game changer in terms of a regional power balance.

“It’s too late for Israel [to prevent an Iranian bomb]. Iran has crossed all the borders and all the constraints, and it has a first nuclear bomb in its possession, and maybe more than that,” Yerushalmi writes, basing himself on what he says is the assessment he heard this week from state security sources. ”We are facing a historic change in the strategic balance of forces in the region.”

He then quotes a source who he says is deeply familiar with what he calls the relentless war against the Iranians. “This is no longer about how to prevent a bomb,” the source is quoted saying, “but about how to prevent its being launched, and what to do if and when.”

Yerushalmi, still basing himself on the anonymous security sources’ assessment, goes on to compare the current behavior of Iran’s Supreme leader Ali Khamenei, and new President Hasan Rouhani, in their interactions with the West, to a soccer coach at the end of a hard-fought match which he knows he has now won. The Iranian leadership is behaving with the air of “those who have achieved their target, and therefore can today afford to be more generous and to offer new (self-serving) messages.” The Iranian leadership can afford to be friendlier, he writes, “because victory has been secured.”

Maariv led its Friday paper with a photograph of a smiling Rouhani, alongside the headline, “What’s hiding behind the smile,” and a sub-headline quoting the security sources saying Iran now has “at least one bomb.” It then adds that most in the security establishment, however, still believe that this “nightmare scenario has not yet been realized.”

While most Western countries believe Iran’s nuclear program is intended for military purposes, officials in Israel, the US and elsewhere say Tehran has yet to “break out” toward a bomb, a process that could take over a year.

Iran, which on Thursday agreed to renewed talks with world powers on curbing its nuclear program, says its program is for peaceful purposes.

On Friday, Iranian and UN officials met to discuss whether to resume inspections meant to determine whether Tehran worked on atomic arms, in a test of pledges by Iran’s new president to reduce nuclear tensions.

Iranian envoy Reza Najafi said in Vienna that it would be unrealistic to expect that “in just one day of meeting we can solve our problems.”

Herman Nackaerts of the International Atomic Energy Agency said only that he hoped the meeting could “intensify the dialogue.”

The UN agency wants access to a site it suspects was used to test conventional explosive triggers meant to set off a nuclear blast.

A report released last month by the IAEA said that while Iran was testing new centrifuges, which could help it eventually create a nuclear weapon, its uranium stockpile was still below the amount needed for a bomb.

“It is unlikely, at this point, that Iran could dash toward further enrichment to weapons-grade without the IAEA detecting Tehran’s activities,” Reuters quoted the Arms Control Association, a Washington-based advocacy and research group.

Israel sees an Iranian nuclear weapon as an existential threat, and Jerusalem has campaigned vigorously around the world for heavy sanctions to be placed on Iran, with a threat of military action should those fail to stop the nuclear program.

Next week, Prime Minister Benjamin Netanyahu is due to deliver a speech at the United Nations during which he is expected to press for maintaining pressure on Iran despite a recent easing of tensions between Tehran and the West. In comments Tuesday, Netanyahu urged the world not to be “fooled” by Iran’s newly moderate rhetoric, which he said was a “smokescreen” to obscure its continued drive toward nuclear weapons.

“Israel would welcome a genuine diplomatic solution that truly dismantles Iran’s capacity to develop nuclear weapons,” Netanyahu said. “But we will not be fooled by half-measures that merely provide a smokescreen for Iran’s continual pursuit of nuclear weapons. And the world should not be fooled either.”

The Associated Press contributed to this report.