US officials revealed that Hezbollah responded to Western warnings that it would not engage in the war against Israel now, despite the continued exchange of missile launches across the Lebanese border.
The US is sending forces and military equipment to "deter" any party from participating in the war that began last Saturday with the Hamas attack against Israeli sites and settlements surrounding the Gaza Strip.
Senior US administration officials do not believe that Hezbollah is likely to join Hamas' war in force against Israel, and officials think the warnings are having an impact even though there has been some escalation on the border.
CNN revealed that the US is sending the message to Hezbollah to stay out of the conflict through several channels, including the Lebanese Prime Minister Najib Mikati and Speaker Nabih Berri.
Berri was mentioned by administration officials briefing Congress on Sunday as a go-between, according to a person familiar with the briefing.
The US won't officially engage with what has been designated a terrorist group, so Berri is one natural conduit.
At Israel's request, France has also conveyed to Hezbollah that they must stay out of the war and not escalate further, or Israel will respond significantly, a source briefed on the talks said.
The discussions were also coordinated with the US, the source said.
"Western allies who have informal ties with Hezbollah have conveyed some messages," a Western diplomat confirmed, adding that the response by Hezbollah indicated "the pre-existing will of Hezbollah not to escalate for now."
A senior defense official said Monday, "We are deeply concerned about Hezbollah making the wrong decision and choosing to open a second front to this conflict," adding: "We are working with Israel and with our partners across the region to contain this to Gaza."
Also, Secretary of Defense Lloyd Austin ordered the deployment of a carrier strike group to the eastern Mediterranean in large part as a message to Hezbollah and its Iranian backers to refrain from entering the war.
"Let me be clear, we did not move the carrier for Hamas," National Security Adviser Jake Sullivan told reporters at the White House on Tuesday.
"We moved the carrier to send a clear message of deterrence to other states or non-state actors that might seek to widen this war."
Analysts said Hezbollah's support for Hamas has been symbolic so far. The party has congratulated Hamas on Saturday's massive attack.
They noted Hezbollah has also exchanged rocket fire across the border with Israel, including rockets fired into Israel on Tuesday, but those attacks appear to be symbolic gestures of support rather than a precursor to severe military action.
CNN quoted Mike Knights saying Hezbollah also provides passive military support by drawing and holding Israel's troops to the northern border and splitting Israel's missile defenses.
Knights is a senior fellow at the Washington Institute specializing in Iran-backed proxy groups.
Former national intelligence manager at Iran for the CIA Norm Roule said: "Logic would tell you that if you're Lebanese Hezbollah, you want to stay out of this conflict."
"You want to let the Israelis and Hamas chew themselves to ribbons, and then you are the strong person standing."
Former CENTCOM Commander Frank McKenzie told CNN on Tuesday that Hezbollah is not particularly invested in Gaza's fate.