BEIRUT, Lebanon - Hassan Nasrallah said his Hizbollah group and Iran were "obliged to respond" to Israel as the Middle East braced for the the pair's promised retaliation following high-profile killings last week.
The United States said earlier it was working "around the clock" to avert an all-out war in the region, following the killings last week of Hizbollah military commander Fuad Shukr in Beirut and Hamas political leader Ismail Haniyeh in Tehran.
Speaking in a televised address to mark one week since Shukr's death, Nasrallah said Tehran "finds itself obliged to respond, and the enemy is waiting in a great state of dread".
Hizbollah was also "obliged to respond", he said, adding that it will retaliate "alone or in the context of a unified response from all the axis" of Iran-backed groups in the region, "whatever the consequences."
Minutes before his speech, Israeli jets flew low over the Lebanese capital, breaking the sound barrier.
Iranian President Masoud Pezeshkian hit out on Monday at what he called the "criminal acts" of Israel "against the oppressed and defenceless people of Gaza", as well as for Haniyeh's killing.
"The Islamic Republic of Iran is in no way seeking to expand the scope of war and crisis in the region, but this regime will definitely receive the response for its crimes and arrogance," Pezeshkian said during talks with a senior visiting Russian official, according to the official news agency IRNA.
Israel has not commented on the Haniyeh killing but confirmed it killed Shukr.
Israel held the Hizbollah commander responsible for a rocket attack in the annexed Golan Heights that killed 12 children, calling him the "right-hand man" of Nasrallah.
'Playing with fire'
Hizbollah has engaged in near-daily cross-border clashes with Israeli troops since the day after Hamas attacked Israel in early October.
The group claimed several attacks on Israel on Tuesday, including one with "explosive-laden drones" targeting a barracks north of the coastal town of Acre.
Regional councils in northern Israel urged residents to stay close to shelters on Tuesday after a barrage of rockets.
In southern Lebanon, six Hizbollah fighters were killed in Israel strikes, according to a Lebanese security source.
Lebanese Foreign Minister Abdallah Bou Habib, on a visit to Cairo, acknowledged that there was "a possibility of a war between us and Israel... We can't deny that."
A European diplomat in Tel Aviv said "a coordinated response" from Iran and its proxies was expected against Israel but de-escalation efforts persisted.
"That doesn't mean there will be a simultaneous response from all fronts," he added, declining to be identified as he was not authorised to speak on the issue.
"We're telling them they have to stop playing with fire, because the risk of flare-ups is higher than at any time since October 7," he said.
Numerous airlines have suspended flights to Lebanon or limited them to daylight hours.
Lebanese national carrier Middle East Airlines put on extra flights for people wanting to leave or return, a company source said.
The Jeddah-based Organisation of Islamic Cooperation is to meet on Wednesday at the request of "Palestine and Iran", to discuss developments in the region, an OIC official said.
The United Nations' rights chief Volker Turk called on "all parties, along with those states with influence, to act urgently to de-escalate what has become a very precarious situation".
