RAMALLAH // Israel’s prime minister said he would “tell the truth” about Tehran’s charm offensive during a White House meeting on Monday with the US president, Barack Obama.

Before departing from Tel Aviv on Saturday evening, Benjamin Netanyahu said he would deliver a similar message in his address to the United Nations General Assembly on Tuesday.

His comments highlight Israeli concern about a fledgling US-Iranian rapprochement that is being driven by conciliatory messages from Hassan Rouhani, Iran’s president. Israel fears this is a ploy by Tehran to ease international sanctions placed on it over its nuclear programme.

“I will tell the truth in the face of the sweet talk and the onslaught of smiles,” Mr Netanyahu said. “One must talk facts and one must tell the truth.”

Coinciding with Mr Netanyahu’s trip, Israel’s Shin Bet domestic security service said on Sunday it had arrested a Belgian citizen of Iranian origin. Shin Bet said Ali Mansouri was sent by Iran to spy on Israel under the guise of a windows and roofing salesman.

During his meeting with Mr Obama, Mr Netanyahu is likely to receive a reassuring message about the thawing ties between Washington and Tehran, which have not had diplomatic relations for 34 years.

Mr Obama and Mr Rouhani spoke by phone on Friday in what was the highest-level contact between the two sides in that time. A day earlier, the US secretary of state, John Kerry, and his Iranian counterpart met in New York.

Israeli media reported on Saturday that US officials alerted Israel before the telephone call between the US and Iranian presidents.

Israel and the West believe Iran is intent on building atomic weapons, but Tehran insists its nuclear programme is for peaceful purposes.

The White House prefers the use of diplomacy to dissuade Iran from pursuing nuclear weapons – a strategy that received a lift from US-Russian agreement to rid Syria of its chemical weapons. In a rare agreement over Syria, the 15-member UN Security Council endorsed that effort on Friday.

But the diplomatic finesse employed by the Obama administration has irked Mr Netanyahu, who has been a proponent of harsh measures – including possible Israeli air strikes – against Iran over its nuclear programme.

“American and Israeli officials like to say there’s no daylight between them on Iran,” a former US official said. “But with his words alone, Rouhani has opened a window.”

Some Israelis fear that Mr Netanyahu could damage their country’s generally robust ties with the US.

Writing in the Haaretz newspaper on Saturday, Chemi Shalev compared the Israeli premier’s pooh-poohing of US-Iranian reconciliation to Debbie Downer, a fictional character on the American comedy sketch television programme Saturday Night Live known for her obnoxious pessimism.

“Only the future can tell whether Netanyahu’s warnings will be borne out or refuted, but in the meantime he runs the risk of being portrayed as a perennial party-pooper and a chronic Cassandra,” Mr Shalev wrote.

hnaylor@thenational.ae

* Additional reporting by Reuters