An Iranian businessman with Belgian citizenship has been arrested for spying on Israel, it has been revealed.

Ali Mansouri was detained at Ben-Gurion International Airport on September 11 as he attempted to leave Israel for Belgium.

He had been spotted photographing the United States embassy in Tel Aviv and filming activity around the city.

According to the Shin Bet, Israel's internal security force, Mr Mansouri was allegedly working for Iran’s Revolutionary Guards, scouting potential terrorism targets, as well as spying on the US’s activity inside Israel.

A Shin Bet official said: “During questioning, the suspect Ali Mansouri described entering Israel under a Belgian identity using the alias Alex Mans, and detailed his recruitment and activation process by Iranian intelligence elements.”

Mr Mansouri allegedly said he was promised $1 million for his spying activities inside Israel. He remains detained at an unknown location.

A gagging order on the arrest was lifted yesterday, coinciding with Israel prime minister Benjamin Netanyahu’s flight to Washington for talks with President Obama .

Mr Netanyahu has warned that Iran still poses a serious threat to Israel and the west, despite Iranian president Hassan Rouhani’s recent display of good will.