Tel Aviv lights up city hall with Lebanon flag
"Humanity precedes any conflict, and our hearts are with the Lebanese people in the wake of the terrible disaster that befell them," Tel Aviv's Mayor Ron Huldai said on Twitter ahead of the event.
Dozens of Israeli passers-by in Rabin Square below city hall looked on as white, red and green lights on the windows of the large building in the centre of the Mediterranean city lit up at 7:55 pm (1655GMT).
Tel Aviv resident Russel told AFP he was "very proud" to live in the city.
"Innocent people were killed and our hearts go out to them. This has nothing to do with politics. This has nothing to do with borders," he said.
"This has to do with people to people and Tel Aviv is a city that loves people."
Not all Israelis supported the city hall's gesture of solidarity.
Israel's minister for Jerusalem affairs, a member of the far-right Jewish Home party, condemned the move following the explosions at Beirut port that killed more than 110 people and injured thousands of others across the city.
"It is possible and necessary to provide humanitarian aid to civilians who were hurt in Lebanon, but waving an enemy flag in the heart of Tel Aviv is moral confusion," Raffi Peretz wrote on Twitter.
Israel and Lebanon are still technically at war, while tensions with the powerful Lebanese Shiite movement Hezbollah have spiked in recent weeks.
Hezbollah and Israel fought a devastating month-long conflict in 2006 in which Lebanon's infrastructure was battered in heavy Israeli air strikes.
The war killed more than 1,200 Lebanese, mostly civilians, and 160 Israelis, most of them soldiers.
But on Tuesday, hours after the tragedy in Beirut, right-wing Prime Minister Benjamin Netanyahu said his National Security Council had offered Lebanon aid, via the United Nations.
Addressing Israel's parliament on Wednesday, Netanyahu extended "condolences to the people of Lebanon" and said Israel remained ready to offer "humanitarian assistance" to those affected.
In Gaza, a Palestinian territory where the poverty rate exceeds 50 percent due at least in part to a crippling Israeli blockade, residents of Khan Yunis organised a blood drive for casualties in Beirut.
Israel tightly controls everything that enters and exits the Islamist Hamas-ruled Gaza Strip, but local authorities in Khan Younis said they were working with the Red Cross and Red Crescent to deliver the donated blood to Lebanon.