Israel's President Isaac Herzog said that the country considers Iran's retaliatory drone and missile strikes 'a declaration of war' in an interview with Sky News on Sunday night.
Despite Herzog saying, "This is like a real war ... I mean, this is a declaration of war," he also added that Israel would exercise restraint.
It is widely believed that Israel will strike back at Iran, but the means and scale of Tel Aviv's response is as yet unknown, with the country's war cabinet having met on Sunday evening.
Iran has Israel that it will no hesitate to launch a larger attack on its territory should it retaliate against Tehran, adding that US bases would be targeted if Washington backs any Israeli military action against Iran, something the Biden administration has seemingly ruled out.
On the Gaza front, Israel's Mossad spy agency said on Sunday that Palestinian group Hamas had rejected the latest proposal by international mediators for a truce in the Gaza war. However, the group has allegedly sent an alternative proposal, with Israel thought to be unwilling to let displaced Gazans return to the north of the enclave.
Israel's brutal offensive on Gaza - which has pulled in Iran-backed groups and seen cross-border clashes in south Lebanon, as well as attacks on vessels in the Red Sea and US troops in Iraq and Syria - has killed over 33,600 people, mostly women and children.