U.S. officials trying to prevent a bigger Middle East war are issuing an unusual warning to Hezbollah: Don’t assume that Washington can stop Israel from attacking you.

The American message is designed to get the Lebanese-based Shiite militia to back down and de-escalate the brewing crisis along the Israeli-Lebanese border, a person familiar with the discussions said.

The blunt message comes as many U.S. officials appear resigned to the possibility that Israel will make a major move against Hezbollah inside Lebanon in the coming weeks.

Two U.S. officials told POLITICO that the militia needs to also understand that Washington will help Israel defend itself if Hezbollah retaliates. They stressed that the militant group should not count on America to act as a brake on Israeli decision-making.

The message is being conveyed indirectly, the person said; the U.S. doesn’t engage Hezbollah one-on-one because it is a designated terrorist organization, and it relies on public communications or intermediaries.

U.S. special envoy Amos Hochstein and other American officials have traveled to the region in recent days to rein in both sides, even as there’s a growing sense in Washington and beyond that escalation is inevitable.

“Israel’s gotta do what they gotta do,” a Defense Department official said, having been granted anonymity, like others, to speak frankly.

Israel and Hezbollah have been clashing at a low level for months, with exchanges of fire and targeted killings that arose when Hamas militants attacked Israel on Oct. 7 and spurred an ongoing Israeli retaliation in the Gaza Strip. The Hezbollah-Israel clashes have spiraled to new heights in recent weeks as Israel’s war against Hamas has fallen in intensity.

U.S. officials fear that a full-blown battle between Israel and Hezbollah, which, like Hamas, is backed by Iran, but is stronger and better armed, could tip the region into an all-out war. That’s a scenario they’ve sought to prevent since the Israel-Hamas war erupted last October.

“We think there ought to be a diplomatic resolution to the conflict across the Israel-Lebanon border that is keeping tens of thousands of families on each side of the border from returning to their homes,” Matthew Miller, the State Department spokesperson, told reporters Monday.

Spokespeople for the State Department and White House National Security Council did not immediately respond to requests for comment on the messaging to Hezbollah.

Israeli Defense Minister Yoav Gallant is in Washington for talks with aides to President Joe Biden, and much of the discussion is likely to focus on the crisis along the Israeli-Lebanese border.

The two U.S. officials said the Biden administration will help Israel defend itself in any scenario with Hezbollah, including everything from replenishing Israel’s Iron Dome missile defense system to providing intelligence. If Israel comes under severe duress — with Hezbollah raining rockets and missiles on its major cities, for instance — the U.S. may move toward more direct military support, the officials said.

Israeli leaders do not appear to have made a final decision on what to do, though none seems to want an all-out war, and neither does Iran, the two U.S. officials said.

When it comes to discussions with the Israelis, “the focus is on injecting reality into Bibi’s calculations,” a separate senior U.S. official said, using the nickname for Israeli Prime Minister Benjamin Netanyahu.

The U.S. intelligence community believes that Hezbollah leader Hassan Nasrallah doesn’t want a war, but assesses that the risk of one is heightened this month as is the risk of a miscalculation on either side, according to another senior U.S. official.

Israel’s military forces are weary after months of war in Gaza, where fighting is far from finished, but in conversations with U.S. officials, Israeli leaders have made compelling arguments for why they need to strike Hezbollah sooner rather than later.

For example: Moves by Hezbollah in the immediate wake of Hamas’ Oct. 7 attack led Israel to evacuate many communities near its border with Lebanon. The loss of that population has undermined the integrity of Israel’s control along that border, a sensitive issue for a country worried about territorial security.

Israel wants the displaced families to be able to return home before the fall; otherwise, they will likely enroll their children in schools where they are now, putting down new roots.

But if Israel strikes Hezbollah, and the militant group fights back in a way that forces even more rounds of fighting, additional Israelis in the area could be displaced.

The Israelis have argued that if the U.S. publicly supports them in an operation — even just backing the threat — then Hezbollah may be more likely to back down or agree to a cease-fire now.

Hochstein, the U.S. envoy, believes he’s making inroads with the Israelis on de-escalating the situation, a person briefed on the situation said. And it’s not unprecedented for the U.S. to successfully hold back an Israeli attack against Hezbollah. U.S. officials talked Israeli leaders out of a major strike against the group in the days immediately after Oct. 7.

This time, however, the Israelis appear more dug in, though it’s possible that the U.S. could affect what type and size of operation they undertake. Past U.S. pressure on Israel managed to affect the scope of some of its other actions, such as in the Gazan city of Rafah or against Iran.

It’s not clear exactly what options Israel is considering against Hezbollah, which is not only heavily armed but also wields political influence in Lebanon. An air operation could help deter the group, while a ground invasion could establish a buffer zone. A combination also is possible.

But Joint Chiefs Chair Gen. C.Q. Brown also had a warning for Israel.

If a broader conflict erupts between Israel and Hezbollah, it may be more difficult for the U.S. to help defend Israel compared with the April 13 missile barrage from Iran, he told reporters traveling with him on Sunday.

That’s because Hezbollah is geographically closer than Iran, therefore an attack requires a shorter response time. Hezbollah also has more rockets than Hamas.