The United States on Thursday reaffirmed its support for a two-state solution after Israeli lawmakers voted to oppose the creation of a Palestinian state as an "existential threat."

"I think the best way I can respond to that is to just reiterate our firm belief in the power and the promise of the two-state solution," said National Security Council spokesman John Kirby.

He declined to directly comment on key ally Israel's vote, which was swiftly criticized by Palestinian leaders and the international community, including the United Nations.

Kirby told reporters that "we're going to keep doing everything we can to try to achieve" a two-state solution.

State Department deputy spokesman Vedant Patel said: "I think it can be safely implied that a piece of legislation that is in opposition to the two-state solution is not something that we would be thrilled about."

Israel's parliament, the Knesset, passed a symbolic resolution on Thursday that said a Palestinian state on land occupied by the Israeli army would "perpetuate the Israel-Palestinian conflict and destabilize the region."

It said "promoting" a Palestinian state "would only encourage Hamas and its supporters" after its October 7 attack on Israel which triggered the Gaza war.

The vote was approved ahead of Israeli Prime Minister Benjamin Netanyahu's visit to Washington next week, during which he will address the US Congress.

The United States is Israel's main political and military backer, but the two countries are fundamentally opposed on the issue of Palestinian statehood.