Senior Israeli defense officials expressed serious concerns over the implications of last week’s summit in Ankara at which the leaders of Iran, Russia and Turkey discussed the aftermath of the Syrian civil war and how the spoils would be divided once the hostilities conclude.

“Iran views the outcome of the Ankara summit as a green light to continue entrenching itself in Syria,” one senior defense official said, calling it “a disconcerting development for Israel.”

Iranian President Hassan Rouhani’s participation in the meeting, alongside Russian President Vladimir Putin and Turkish President Recep Tayyip Erdogan, is perceived by the defense establishment not only as a sign of gratitude to Iran for its efforts to help salvage the Assad regime in Syria, but also as a guarantee of Iran’s future role there.

“The fact that Iran is participating in such a summit, under Russia’s wing, gives the Iranians the tailwind to continue on their current path,” an Israeli official said. “This is a blatant, dangerous empowerment of negative forces in the region.”

According to the official, Russia may not have an interest in establishing significant Iranian power in Syria, but it “not only is not doing anything to stop this process, it is actually hastening it.”

In recent months, Israeli officials have been gravely concerned by Iran’s efforts to build permanent military bases inside Syria. These efforts have already prompted direct confrontations between Israel and Iran: In December, an Iranian base near Damascus was hit in a strike attributed to Israel. In February, Israel downed an Iranian drone that had breached Israeli airspace. Israel also destroyed the drone’s remote guidance system and two additional Iranian targets in Syria.

As these strikes have not curbed Iranian efforts to establish a presence in Syria, Israel has communicated resolute, diplomatic and open messages, first and foremost the U.S. and Russia, that it will continue safeguarding its interests and will act to foil Iran’s activities.

Israeli defense officials believe the only power capable of curbing or blocking Iran’s regional aspirations is the United States, but so far, Israel has had little success in its efforts to enlist the U.S. to take an active role in Syria.

“The other side is seeing this American weakness loud and clear and, it is enhanced further by the Russians’ embrace, giving these negative forces, led by Iran, a lot of confidence,” an Israeli official said.

“The other side takes note of American weakness very well, and along with the Russian embrace, it gives the negative forces, led by Iran, a lot of confidence.”

As a result, Syrian President Bashar Assad feels free to use chemical weapons on his people again and again, one official said, calling Assad’s behavior “a finger in the eye of the Americans, and a reason for us to worry.”