With the specter of an American attack in Syria looming, Prime Minister Benjamin Netanyahu on Sunday drew attention to the partners of the embattled Syrian leader, Bashar Assad: Iran and the Lebanese militia Hezbollah.

“Assad’s regime isn’t acting alone,” Netanyahu told journalists after a meeting with French Foreign Minister Laurent Fabius. “Iran, and Iran’s proxy, Hezbollah, are there on the ground playing an active role assisting Syria. In fact, Assad’s regime has become a full Iranian client and Syria has become Iran’s testing ground.”

Netanyahu’s announcement came amid persistent reports of a chemical weapons attack last week outside Damascus that killed hundreds of people. A US official said Sunday there was “very little doubt” that Assad had been behind the attack, which has prompted US naval forces to move closer to Syria.

“Now the whole world is watching,” Netanyahu said Sunday. “Iran is watching and it wants to see what will be the reaction to the use of chemical weapons.”

The prime minister went on to compare the Syria use of chemical weapons to Iran’s alleged pursuit of nuclear weapons: “What is happening in Syria, simply demonstrates what will happen if Iran gets even deadlier weapons.”

“Our hand is always on the pulse,” Netanyahu said earlier Sunday. “Our finger is a responsible one and if needed, is on the trigger. We will always know how to protect our citizens and our country against those who come to injure us or try to attack us.”

Israel, like the rest of the world, has refrained from responding to the Syrian civil war in any large-scale way, taking in only a small number of injured Syrians and reportedly carrying out covert air strikes at regime weapons sites. Yet officials have said action must be taken, with most expecting Washington to respond to the attack.

Speaking to journalists after the meeting, Fabius called the alleged attack a “chemical massacre,” and said that during his stay in the region he remained in close contact with officials across the world regarding a response.

“I can confirm that the testimonies all point to the fact that there was a massacre committed through chemical gas in Syria, and the fact that the regime of Bashar Assad was responsible for this massacre. I can also promise you, without going into detail, that it is unthinkable that such crime shall remain without a strong response.”

He added that he had “no doubt” about who had committed the attack.

Defense Minister Moshe Ya’alon also met with Fabius and asserted that Israel would defend itself if attacked by Assad. He added that last week’s alleged gas attack wasn’t the first time the Assad regime had used such weapons.

Ya’alon said Israel would not intervene in Syria’s ongoing civil war. Referring to the lines in the lines in the sand previously drawn by his government, he said: “We won’t allow the transfer of quality weapons to Hezbollah and other terror groups, we won’t allow the transfer of chemical weapons and we’ll respond to any action that hurts our sovereignty.”

At the end of the day, the defense minister said, “we have do defend ourselves on our own, and do so responsibly and thoughtfully. We don’t expect foreign armies to do it for us.

“There are a lot of events occurring in our region, especially the use of nonconventional weapons by a nonconventional regime, a move that caused the tragic death of hundreds of innocent civilians,” Ya’alon said. “This is not the first time the regime in Syria, supported by Iran and Hezbollah, [is] using unconventional weapons.”

Fabius also met with Finance Minister Yair Lapid, who called the ongoing civil war “a tragedy that needs to be stopped.” Lapid said “dangerous regimes like the one in Syria” shouldn’t have “a dangerous weapon which hurts thousands of innocent civilians.”

Earlier in the day, opposition head Shelly Yachimovich (Labor Party) told Fabius the world “cannot remain silent” when faced with the news from Syria. “I told him it was genocide,” she said in a statement.

Yachimovich said France’s top diplomat “absolutely identified with [that idea,” and that despite the sensitive geopolitical situation “his country won’t accept a situation where there’s no hard response to these actions.”

The Labor Party head also told Fabius she and her party “will be Prime Minister Benjamin Netanyahu’s safety net” to enable him to move forward and strive for peace. Yachimovich pointed out “the obvious difference” between Israel and the rest of the countries in the region, noting that even with criticism directed at Jerusalem, it was still the only democracy in the area.