Iran's supreme leader vowed in a rare address on Friday that his allies around the region would keep fighting Israel, as he defended his country's missile strike on its foe.

Ayatollah Ali Khamenei's address in Tehran followed Iran's second-ever direct attack on Israel. It was also the first since exchanges of fire between Tehran-backed Hezbollah fighters and Israeli troops escalated into full-blown war in Lebanon.

Speaking ahead of the first anniversary of Hamas's October 7 attack on Israel that triggered the ongoing war in the Gaza Strip, Khamenei defended the Palestinian group's "logical and legal" actions and hailed its "fierce defence" against Israeli forces.

The unprecedented Hamas attack resulted in the deaths of 1,205 people, triggering global condemnation but also supporting fire from Iran-backed groups around the Middle East, mainly Lebanon's Hezbollah and Yemen's Huthi rebels.

Hezbollah on Friday said it clashed again with Israeli troops on the Lebanese border.

Early Saturday, AFP correspondents in the Lebanese capital heard two explosions and saw smoke rising over Beirut's southern suburbs, after Israeli army Arabic-language spokesperson Avichay Adraee warned residents in part of the area's Burj al-Barajneh neighbourhood to evacuate.

In Jordan and Bahrain, which both have ties with Israel, crowds gathered after Friday prayers in a show of support for Hamas and Hezbollah.

In Amman, demonstrators carried posters hailing the "glory and dignity" of the October 7 attack.

Nearly a year into the Gaza war, Israel has shifted its focus north, aiming to allow tens of thousands of Israelis displaced by cross-border Hezbollah rocket attacks to return home.

Israel's military launched an intensified wave of strikes on Hezbollah strongholds around Lebanon, killing more than 1,110 people since September 23, and forcing hundreds of thousands to flee their homes in a country already mired in economic crisis.

The attacks have killed an Iranian general, a host of Hezbollah commanders and, in the biggest blow to the group in decades, its leader, Hassan Nasrallah.

- Strikes in Yemen -

"The resistance in the region will not back down with these martyrdoms, and will win," Khamenei said in Arabic.

He charged that Israel was a "malicious regime" that would "not last long".

There was no immediate response from Israeli leaders as much of the country celebrated the Jewish new year.

Khamenei's address came as Israel weighs retaliation for Iran's missile attack on Tuesday, which Tehran called revenge for the killing of Nasrallah and other top figures.

One person was reported killed in the Iranian barrage.

Satellite pictures of Nevatim air base in southern Israel showed apparent damage to a structure on Wednesday, compared with a photo taken on August 3.

United States President Joe Biden, whose country is Israel's biggest military supplier, on Friday urged Israel against striking Iran's oil facilities, a day after he said Washington was "discussing" the possibility of such strikes.

But Republican White House hopeful Donald Trump said the same day he believed Israel should "hit" Iran's nuclear sites.

Iran's Foreign Minister Abbas Araghchi visited Beirut and said his government backs "the efforts for a ceasefire" that would be acceptable to Hezbollah and come "simultaneously with a ceasefire in Gaza".

Biden said the US was working to "rally the rest of the world and our allies" to prevent the fighting from spreading even further.

The US military on Friday said it struck 15 targets in areas of Yemen controlled by Huthi rebels, who have fired missiles at Israel and repeatedly attacked global shipping in the Red Sea.

US, Qatari and Egyptian mediators tried unsuccessfully for months to reach a Gaza truce and secure the release of hostages still held by Hamas.

- Border crossing closed -

In Beirut, 35-year-old displaced nurse Fatima Salah said people were "scared for our children, and this war is going to be long".

Sina Toossi, a senior fellow at the Center for International Policy in Washington, told AFP: "Everything right now hinges on Israel's response, whether it escalates into a regional war."

In Lebanon, Israeli bombardment has put at least four hospitals out of service, and on Friday, a first delivery of medical aid organised by the United Nations reached Beirut airport.

Lebanon said an Israeli strike on Friday cut off the main international road to Syria, with Israel saying it aimed to prevent the flow of weapons.

Lebanon's disaster management unit said more than 374,000 people -- most of them refugees from Syria's war -- crossed back into the relative safety of their home country in the final week of September.

In Hezbollah's bastion in Beirut's southern suburbs, US and Israeli media reports said intense bombardment had targeted the militant group's potential successor, Hashem Safieddine, a week after Nasrallah's killing.

The Israeli military has not commented on that strike.

- 'Scandalous' -

Israel announced this week that its troops had started ground raids into parts of southern Lebanon, a Hezbollah stronghold.

On the Israel-Lebanon border, the Israeli military said its forces had killed 250 Hezbollah fighters this week and hit "over 2,000 military targets".

Hezbollah on Friday said its fighters again clashed with Israeli soldiers during "infiltration" attempts.

The group also said it kept up its rocket fire, and Israel's military reported about 200 projectiles fired into Israel on Friday.

The Islamic Health Committee, a Hezbollah-affiliated emergency service, reported that 11 of its personnel were killed Friday by Israeli strikes in southern Lebanon.

The Israeli military said nine soldiers have been killed in combat in Lebanon.

Separately, a drone launched "from the east" killed two Israeli troops, the army said Friday. An Israeli public broadcaster said the strike originated in Iraq.

In the Israeli-occupied West Bank, which has endured intense military raids throughout the Gaza war, the Palestinian health ministry said an air strike killed 18 people in the Tulkarem refugee camp.

Germany described as "shocking" the number of civilian casualties, and the United Nations rights office called the strike "unlawful". Israel said it had targeted a local Hamas leader.

In Gaza, Israel's retaliatory offensive has killed at least 41,802 people, the majority of them civilians, according to figures provided by the Hamas-run territory's health ministry. The United Nations has described the figures as reliable.

An official with Medical charity Doctors Without Borders (MSF) told AFP life was becoming "impossible" in Gaza, urging greater humanitarian efforts.

In a separate statement, MSF denounced the "scandalous inaction and duplicity" of the international community.