An American envoy came to Israel two weeks ago and held talks with senior Israeli officials about establishing de-escalation zones, otherwise known as safe zones, in southern Syria near the Israeli and Jordanian borders as part of an effort to end Syria’s civil war.

Israel told Washington that it opposes having Russian forces supervise what happens in these zones, senior Israeli officials said.

The idea of establishing de-escalation zones arose after U.S. President Donald Trump took office in January. Both the White House and the Kremlin have pushed this idea as a way to end the civil war. In early April, Haaretz reported that Prime Minister Benjamin Netanyahu expressed receptiveness to the idea to both Washington and Moscow, viewing it as a way to keep Iran and Hezbollah away from Israel’s border.

Three senior Israeli officials involved in the issue, who asked to remain anonymous, said the talks about establishing de-escalation zones became more serious and intense last month, due to quiet discussions among America, Russia and Jordan on the issue. Israel isn’t actively involved in these talks, but has been briefed on them, they added.

Israel’s main interlocutor on this issue is the U.S. administration. The Defense Ministry and the Israel Defense Forces are in charge of the talks, but the Foreign Ministry is also involved.

A senior Israeli official said the talks are taking place in great secrecy and very intensively, including in the last few days. He said Washington is coordinating its positions with Jerusalem and presenting Israel’s views in its talks with Russia and other international players.

Two weeks ago, Brett McGurk, America’s special envoy for the global coalition to counter Islamic State, came to Israel to speak at the annual Herzliya Conference and used the opportunity to meet with senior Defense Ministry, Foreign Ministry and IDF officials about the de-escalation zones.

A few weeks earlier, Michael Ratney, America’s special envoy for Syria, came to Israel for similar meetings on this topic. The issue also arose during Defense Minister Avigdor Lieberman’s meeting in Munich last week with U.S. Secretary of Defense James Mattis.

In talks with McGurk and others, Israel raised three main demands.

First, it wants talks on de-escalation zones along the Israeli and Jordanian borders to be completely separate from the current negotiations in Astana, the capital of Kazakhstan, in which Iran and Turkey are heavily involved. It also opposes any Iranian or Turkish involvement in determining the nature of the de-escalation zones in southern Syria. Washington has accepted this position and is essentially holding separate talks with Moscow and Amman over the zones in southern Syria.

Second, Israel wants the de-escalation zones in southern Syria to keep Iran, Hezbollah and other Shi’ite militias away from the Israeli and Jordanian borders.

Finally, staying out of Syria’s civil war is one of Israel’s red lines, so Israel doesn’t want any active role in operating or policing the de-escalation zones near its border.

One of Israel’s main concerns is how the cease-fire would be enforced in areas near the Israeli and Jordanian borders and who would be responsible for enforcing it. A senior Israeli official said Russia has proposed that its army handle the job in southern Syria. But Israel vehemently opposes this idea and has made that clear to the Americans, he said.

Israel would prefer to have American troops enforce the cease-fire in southern Syria. The Trump Administration is considering this idea, but hasn’t yet decided.

Trump will meet with Russian President Vladimir Putin in Hamburg on Friday. On Thursday, in advance of this meeting, Secretary of State Rex Tillerson issued a statement indicating that America might consider sending troops to the de-escalation zones.

“The United States is prepared to explore the possibility of establishing with Russia joint mechanisms for ensuring stability, including no-fly zones, on the ground cease-fire observers, and coordinated delivery of humanitarian assistance," he said.

Israel believes the outcome of the Trump-Putin meeting will determine whether the idea of de-escalation zones is seriously pursued. Netanyahu discussed the idea with Putin by telephone on Thursday.

“There are a lot of talks on this issue, but nothing has come to fruition yet,” a senior Israeli official said. “The information we’ve received to date was general, and in this case, too, the devil is in the details, so we’ll want to see exactly what commitments we’re getting.

“We’re in close contact with the Americans and they understand our positions and our concerns very well,” he added. “We made it clear to the Americans and other parties that we want to see the entire package relating to the de-escalation zones, not just a few details, and then we can decide what our position is.”