Israel said on Saturday it had struck military targets inside Iran in response to earlier Iranian attacks, again raising fears that the long-running confrontation between the two powerful militaries could escalate into an all-out regional war that draws in the United States.

The Israeli attacks followed Iran’s ballistic missile barrage against Israel this month, adding to the cycle of tit-for-tat strikes between the two countries.

Iran is bracing for a retaliatory attack by Israel, which analysts say will probably target military sites rather than nuclear or oil facilities.

Israel’s attack on Iran targeted military sites, according to U.S. officials, and appeared to bypass nuclear and energy sites that the Biden administration had urged Prime Minister Benjamin Netanyahu's government not to strike.

Tehran has several plans for responding to a threatened retaliatory strike by Israel, depending on its severity, and might also do nothing, insiders say.

Iran's Supreme Leader Ayatollah Ali Khamenei has reportedly directed the country's armed forces to prepare contingency plans for a potential missile strike against Israel, following rising tensions after Iran's recent ballistic missile attack on October 1.