Britain, Australia and Canada on Sunday recognized a Palestinian state in a seismic shift in decades of Western foreign policy, triggering swift Israeli anger.

Portugal was also set to recognize Palestinian statehood later Sunday, as Israel came under huge international pressure over the nearly two-year-long Gaza conflict.

"Today, to revive the hope of peace for the Palestinians and Israelis, and a two-state solution, the United Kingdom formally recognizes the State of Palestine," UK Prime Minister Keir Starmer said in a message on X.

The decision carries symbolic weight, as Britain played a major role in Israel's creation as a modern nation in the aftermath of World War II and has long been its ally.

Palestinian President Mahmoud Abbas said on Sunday that Britain's recognition of a Palestinian state was a necessary step towards lasting peace in the region.

Husam Zomlot, head of the Palestinian Mission in London, called the decision a "long-overdue recognition" that "is not about Palestine, but about Britain's fulfilment of a solemn responsibility."

"It marks an irreversible step towards justice, peace and the correction of historic wrongs," he added in a statement.

Britain and Canada became the first G7 countries to take the step, with France and other nations expected to follow at the annual UN General Assembly, which opens Monday in New York.

"Canada recognizes the State of Palestine and offers our partnership in building the promise of a peaceful future for both the State of Palestine and the State of Israel," Canadian Prime Minister Mark Carney wrote on X.

It is a watershed moment for Palestinians and their decades-long ambitions for statehood, with the most powerful Western nations having long argued it should only come as part of a negotiated peace deal with Israel.

But the move puts those countries at odds with the United States and Israel, with Israeli Prime Minister Benjamin Netanyahu reacting angrily and vowing to oppose it at the UN talks.

Calls for a Palestinian state "would endanger our existence and serve as an absurd reward for terrorism," Netanyahu said Sunday.

A growing number of longtime allies have shifted positions as Israel has intensified its Gaza offensive, vowing to eliminate Hamas.

The Gaza Strip has suffered vast destruction, a spiraling death toll, and a lack of food that has sparked a major humanitarian crisis, drawing an international outcry.

(With input from agencies)