The leader of the Iran-backed Shia Muslim group Hezbollah in Lebanon has suggested its readiness to strike against Israel following the killing of its senior commander and the top political leader of Hamas.

Hassan Nasrallah said on Thursday that the battle has entered a new phase and the enemy should expect retaliation.

The Israeli military said on Tuesday that it "eliminated" the Hezbollah commander in a targeted airstrike on Lebanon's capital, Beirut.

Hamas, which is fighting Israeli forces in the Gaza Strip, said on Wednesday that political leader Ismail Haniyeh was killed by Israel during his visit to Tehran.

Israel has not claimed responsibility for the attack in the Iranian capital, but Iran's Supreme Leader Ayatollah Ali Khamenei said his people consider it their duty to avenge Haniyeh's death.

Reuters news agency reported on Thursday that top Iranian officials will meet the representatives of Tehran's regional allies, including Hezbollah, to discuss potential retaliation against Israel.

The chief of staff of the Iranian Armed Forces said the response of his country and the resistance front is being reviewed.

Israeli Prime Minister Benjamin Netanyahu said his country "is in a state of very high readiness for any scenario," and that it "will exact a very high price for any act of aggression."