Iran's Supreme Leader Ayatollah Ali Khamenei has warned of further retaliation against Israel.

Khamenei delivered a speech in Tehran on Friday to commemorate late Hezbollah leader Hassan Nasrallah, who was killed in an Israeli airstrike in Lebanon.

Khamenei referred to Iran's Tuesday missile strikes against Israel, and said it was completely legal and legitimate, adding that a right and reasonable action will be taken again if necessary.

The remark came as Israel has said it will retaliate against Iran's missile attacks.

The Israeli military is also stepping up its offensive against Hezbollah in Lebanon. It's launched a ground operation in the country's south and bombardments on the capital, Beirut, and other places.

The New York Times quoted Israeli officials as saying the military bombed an underground bunker near Beirut after gaining information that senior Hezbollah officials were holding a meeting. It also reported the meeting included a person who may become the successor to Nasrallah.

Hezbollah is believed to be fighting with Israeli troops in southern Lebanon while firing rockets and other weapons toward Israel.

In Lebanon, nearly 1.2 million people have been forced to evacuate. The humanitarian crisis there is becoming more serious.

Meanwhile, US President Joe Biden was asked by reporters on Thursday whether he would support Israel striking Iran's oil facilities. He said his administration was discussing the matter. Following the comment, crude futures rose as the view spread that oil production sites could possibly be targeted.