The officials said it would be challenging for the Israelis to defend against an attack of such a magnitude and while they held out the possibility that the Iranians could opt for a smaller-scale attack to avoid a dramatic escalation, their retaliation was believed to be imminent.
Iran has publicly threatened to retaliate for an attack last week in Damascus, Syria, that Tehran said was an Israeli air strike on a diplomatic building and in which top Iranian military officials, including a senior member of the Islamic Revolutionary Guard Corps, were eliminated.
On Thursday night, The Wall Street Journal reported Israel is preparing for a direct attack from Iran on southern or northern Israel as soon as the next 24 to 48 hours, a person familiar with the matter said.
A person briefed by the Iranian leadership, however, said that while plans to attack are being discussed, no final decision has been made.
Earlier on Thursday, Iranian sources told Reuters that Iran has signaled to Washington that it will respond to the attack attributed to Israel on its Syrian embassy in a way that aims to avoid major escalation and it will not act hastily.
Iran's message to Washington was conveyed by Iranian Foreign Minister Hossein Amir-Abdollahian during a visit on Sunday to the Gulf Arab state of Oman, which has often acted as an intermediary between Tehran and Washington, the sources said.
