The Biden administration is seeking to align its position with Israel on any potential response to Iran's attack but also recognizes the Middle East is on a "knife's edge" and a broader escalation could imperil both Israeli and U.S. interests, U.S. Deputy Secretary Kurt Campbell said on Wednesday.

Speaking at a virtual event hosted by Washington-based think tank Carnegie Endowment, Campbell repeated the U.S. view that what Tehran has undertaken was "deeply irresponsible" and that there must be a "return message."

"I think we recognize, as important as a response of some kind should be, there is a recognition that the region is really balancing on a knife's edge, and real concerns about a even broader escalation or a continuing one, not just simply an exchange of sort of isolated salvos, but of more sustained hostility, which could imperil not just Israel, but our strategic interests as well," Campbell said.

The Middle East is teetering on the brink of a regional war after Iran fired more than 180 missiles into Israel on Tuesday, its biggest ever assault on Israel, triggering a vow from Jerusalem and Washington to hit Tehran back hard.

The Israeli army is also locked in combat at its northern border with Lebanon-based armed group Hezbollah. On Wednesday, eight Israeli soldiers were killed – the deadliest suffered by Israel's military on the Lebanon front in the past year of border-area clashes between Israel and its Iranian-backed Lebanese foe.

The attacks from Lebanon into Israel have been "destabilizing," Campbell said, while issuing a warning about sustained conflict with Lebanon.

"I think we tried to underscore our support for some of the actions that Israel has taken. I think we have real wariness about a extended or substantial ground set of operations in Lebanon," Campbell said.