Iran's supreme leader Ayatollah Ali Khamenei delivered remarks in Arabic in a rare Friday sermon after the Farsi-speaking Islamic republic had launched a missile attack on foe Israel.

During the sermon at a mosque in Tehran, Khamenei hailed Iran-backed armed group Hezbollah and Hamas, which are both fighting Israel and operate in Arabic-speaking Lebanon and the Gaza Strip, respectively.

Hezbollah said it shelled Israeli troops in a border area of south Lebanon Friday, in the latest such clash on the frontier.

The group said its fighters targeted "Israeli enemy troops in the Maroun al-Ras plain with artillery".

A source close to Hezbollah said Friday the group's slain chief Sayyed Hassan Nasrallah has been temporarily buried in a secret location fearing Israel would target a large funeral.

"Hassan Nasrallah has been temporarily buried, until the circumstances allow for a public funeral," the source said, after an Israeli strike killed the leader last week.

Iran's Foreign Minister Abbas Araghchi landed in Lebanon's capital Friday, official media said, as Israel intensifies its air strikes against the Tehran-backed Hezbollah group in Lebanon.

"An Iranian plane has landed at the Rafik Hariri International Airport with Foreign Minister Abbas Araghchi on board," the Lebanese National News Agency said of the first visit by a top Iranian official since an Israeli strike killed Hezbollah chief Sayyed Hassan Nasrallah in Beirut last week.

A source close to Hezbollah said Israel had conducted 11 consecutive strikes on the group's south Beirut stronghold late Thursday, in one of the most violent raids since Israel intensified its bombardment campaign last week.

Three Israeli officials told U.S. news portal Axios that Hezbollah senior official Sayyed Hashem Safieddine was the target of the strike.

The Lebanese army said an Israeli strike killed one of its soldiers during a rescue operation with the Red Cross in southern Lebanon on Thursday.

"A soldier was killed and another was wounded as a result of an aggression by the Israeli enemy during an evacuation and rescue operation with the Lebanese Red Cross in Taybeh village," the army said.

Hezbollah said it fired a barrage of rockets at the Israeli city of Tiberias on Thursday, while more than three Israeli air strikes hit south Beirut, following a night of intense bombardment.

Hezbollah said it "fired a salvo of rockets at the city of Tiberias," it said, in response to the Israeli bombardment of Lebanese "towns, villages and civilians".

The Israeli military on Thursday said a strike three months ago killed three senior Hamas leaders in Gaza, where the army has been battling the Palestinian militants for nearly a year.

The military said the strike killed Rawhi Mushtaha, the head of the Hamas government in the Gaza Strip, and Sameh al-Siraj, who held the security portfolio for Hamas's political bureau, and Sami Oudeh, a commander.

The European Union on Thursday said it was giving an extra 30 million euros ($33 million) of humanitarian aid to Lebanon as fighting raged between Israel and Hezbollah.

"Today, we are stepping up our humanitarian aid to the people of Lebanon," said European Commission president Ursula von der Leyen.

The Israeli military said Thursday it conducted an air strike that killed 15 Hezbollah fighters in Lebanon.

The air force "precisely struck the Bint Jbeil municipality building in which Hezbollah terrorists were operating, alongside large quantities of Hezbollah weapons stored in the building. As part of the strike, approximately 15 Hezbollah terrorists were eliminated," said the statement.