Israel’s army chief on Sunday landed in the United States for talks with his American counterpart, amid tension with Syria following a reported Israel airstrike there last week. He arrived as Israel’s defense minister insisted that Israel “means what it says” about preventing advanced weaponry being moved into Lebanon as Bashar Assad’s regime in Damascus loses control.

IDF chief of General Staff Lt.-Gen. Benny Gantz began a five-day work visit in the United States as the guest of the chairman of the Joint Chiefs of Staff, Gen. Martin E. Dempsey, the IDF announced on Sunday afternoon.

It said Gantz and Dempsey would hold “a series of work meetings together” and with other American officials, and would “discuss current security challenges, the regional security status in the Middle East and military cooperation.”

Gantz was accompanied by the head of the IDF’s Planning Directorate, Maj.-Gen. Nimrod Sheffer.

Apart from the Syria crisis, the two military chiefs will likely also focus on Iran’s nuclear weapons drive. Formally starting the process of building his new government on Saturday night, Israel’s Prime Minister Benjamin Netanyahu said stopping Iran would be his first priority. Late last summer, amid reports that Netanyahu wanted to launch military action against Iran, Dempsey publicly and dramatically declared that he would not want to be “complicit” in any such Israeli action.

Israel’s reported airstrike overnight Tuesday is said to have targeted a convoy carrying advanced anti-aircraft defense systems toward Lebanon, presumably to Hezbollah. Syria said the IAF hit a scientific research center in Jamarya, northwest of Damascus, and on Saturday it released purported video footage of the scene. Other reports have indicated that further sites were targeted, including a biological weapons research center.

A Time magazine article on Friday claimed Washington has given Israel a “green light” to carry out more such raids if it deems them necessary. It said the US was prepared to carry out raids of its own in the Aleppo area if it feared rebels might otherwise gain control of weapons of mass destruction in that part of Syria.

On Wednesday, US officials told The New York Times that Israel notified the United States in advance about the airstrike it carried out. An unnamed Western official told The Wall Street Journal that the convoy was carrying sophisticated Russian-made SA-17 anti-aircraft weapons, which could constitute a strategic game-changer were Hezbollah to possess them.

Israel has not confirmed Tuesday’s alleged air raid. But Defense Minister Ehud Barak hinted Sunday at Israel’s involvement.

Speaking at a security conference in Munich, Barak said, “What happened in Syria several days ago… that’s proof that when we said something we mean it — we say that we don’t think it should be allowed to bring advanced weapons systems into Lebanon,” he said.

Barak added that he saw the fall of Syrian President Bashar Assad as imminent, and that it would be a major blow to Iran. He added that “Hezbollah from Lebanon and the Iranians are the only allies that Assad has left.”

He said in his view Assad’s fall “is coming imminently” and when it happens, “this will be a major blow to the Iranians and Hezbollah.”

Assad responded to last week’s alleged Israeli strike for the first time on Sunday while speaking with Iranian envoy Saeed Jalili in Damascus. He said that Israel’s aggression “exposes the true role conducted by Israel in collaboration with the external forces hostile [to Syria] in destabilizing security in Syria and weakening it so that it forgoes its national principles.”

“Syria is capable of withstanding any foreign aggression through the awareness of its people and its steadfastness in clinging to the course of resistance,” he said.

Iran on Thursday threatened “grave consequences for Tel Aviv” after the airstrike.