TEL AVIV – An airstrike on what was said to be an Iranian military base in Syria was carried out by the Israel Air Force using F-15 fighter jets, three American officials told NBC news on Tuesday.

The officials, who spoke on condition of anonymity, said Israel is preparing for a possible war with Iran. Senior officials, including Defense Minister Avigdor Liberman, have made several trips to the U.S. in an attempt to solicit American support. U.S. officials have also visited Jerusalem recently.

Sunday’s strike targeted an arms shipment from Iran that included surface-to-air missiles, NBC reported. The shipment was sent to a base close to the city of Hama belonging to the Syrian army’s 47th Brigade that is said to have doubled as a headquarters for Iran. Two dozen troops, including officers, were killed in the strike and three dozen others were wounded.

“On the list of the potentials for most likely live hostility around the world, the battle between Israel and Iran in Syria is at the top of the list right now,” one of U.S. officials told NBC.

U.S. and Israeli intelligence have been monitoring cargo flights from Iran to Syria, fearing they are stocked with weapons to be used against the Jewish state.

CivMilAir, a social media site that tracks “rare and interesting aircraft” around the world, recorded two flights by Syrian Air Force IL-76 cargo jets between Iran and Syria the day before the strike. At least one Iranian cargo jet was tracked by the Pentagon on the same route, according to a report by CNN.

A Syrian pro-regime official told the New York Times that the strike destroyed 200 missiles. Iran was likely to retaliate over the bombing, the official said.

As was the case with a strike last month on the T-4 airbase, Israel has not commented on Sunday’s attack.

Syria, Iran, Russia and some U.S. officials said Israel was behind the T4 strike.