Supreme Leader Ayatollah Ali Khamenei said on Friday that Iran and its regional proxies will not back down from Israel hours after an Israeli attack on Beirut that is thought to have targeted the heir apparent to Tehran-backed Hezbollah's slain secretary general.

"The brilliant action of our armed forces a couple of nights ago was completely legal and legitimate," Khamenei said in a rare appearance leading Friday prayers in Tehran, referring to Iran's missile attacks on Israel on Tuesday.

U.S. President Joe Biden said on Thursday Israel's response could include a strike on Iran's oil facilities.

Beirut's southern suburb of Dahiye, a stronghold of the Iran-backed Hezbollah, came under renewed strikes near midnight on Thursday after Israel ordered people to leave their homes in some areas, residents and security sources said.

The air raids targeted Hezbollah official Hashem Safieddine, rumored successor to its assassinated leader Hassan Nasrallah, in an underground bunker, Axios reporter Barak Ravid said on X, citing three Israeli officials.

Safieddine's fate was not clear, he said.

Israel's military declined comment and Hezbollah made no comment on Safieddine's fate. His brother Sayyed Abdallah Safieddine, who is Hezbollah's representative to Iran, attended Khamenei's speech in Tehran.

Huge explosions shook the sky in the vicinity of Beirut's main airport in the early hours of Friday, and Lebanese civilians said they were living in constant fear.

U.S. President Joe Biden said he did not believe there is going to be an "all-out war" in the Middle East, as Israel weighs options for retaliation, but that more needed to be done to prevent one.

While the United States, the European Union, and other allies have called for an immediate 21-day ceasefire in the Israel-Lebanon conflict, Biden said the U.S. was discussing with Israel its options for responding to Tehran's assault, which included Israel striking Iran's oil facilities.

His comments contributed to a surge in global oil prices, and rising Middle East tension has made traders worry about potential supply disruptions.

However, Biden added: "There is nothing going to happen today." Asked later if he was urging Israel not to attack Iran's oil installations, Biden said he would not negotiate in public.