Quiet sobs during memorial speeches, mourning crowds lighting candles... Israel fell silent briefly on Tuesday, marking one month since the deadly Hamas attacks of October 7 plunged it into war.

At Jerusalem's Hebrew University around 1,000 people observed a minute of silence and recited prayers for the 1,400 killed, mostly civilians, in the worst attack on Israel since its founding in 1948.

"The atrocities left a horrible mark," said university president Asher Cohen. "But there is hope. There will be rebirth."

Israel said Tuesday its forces were operating "in the heart of Gaza City" one month after Hamas's bloody October 7 attacks, as the campaign to crush the Palestinian militants intensifies.

Prime Minister Benjamin Netanyahu also issued a stark warning to Hezbollah in Lebanon which, like Hamas, is backed by Iran.

"If Hezbollah makes the choice of joining the war it will be making the mistake of its life," he said in a televised statement marking a month of the war.

His defence minister, Yoav Gallant, underlined Israel's determination "to destroy Hamas".

US Secretary of State Antony Blinken called Tuesday on the G7 to speak "in a clear voice" about the Israel-Hamas war as he kicked off talks with fellow foreign ministers from the grouping in Japan.

"This is a very important moment... for the G7 to come together in the face of this crisis and speak as we do in one clear voice," Blinken said at the start of the two-day meeting in Tokyo.

One month into the Israel-Hamas war, the achievements of US-led diplomacy have been small or subtle, but both supporters and critics say that is partly by design.

US Secretary of State Antony Blinken, completing his second whirlwind crisis tour, insisted that all leaders he spoke to wanted "American leadership."

"Every country I talk to is looking for us to play a leading role with our diplomacy to try to make progress on all of these different aspects of the crisis," Blinken told reporters Monday in Ankara.

Hundreds of US Jewish activists peacefully occupied New York's Statue of Liberty on Monday to demand a ceasefire by Israel and an end to the "genocidal bombardment" of civilians in Gaza.

Dressed in black T-shirts emblazoned with the slogans "Jews demand ceasefire now" or "Not in our name," the protestors unfurled banners reading "The whole world is watching" and "Palestinians should be free" at the base of New York's iconic landmark.

The huge copper statue sits on Liberty Island at the entrance to New York Harbor.

The Israeli army is engaged face to face with Hamas fighters on the edges of Gaza City, foreshadowing what analysts describe as an extreme phase of urban combat with grave risks for both sides.

In the north of Gaza City, ground combat is well underway, according to Israeli army spokesman Daniel Hagari.

"We are talking about fighting where we see each other from one building to the other," he told the press.

Israel has launched ground troops into Gaza as it presses on in the month-long war that was sparked by Hamas's unprecedented attack on southern Israel on October 7.

UN Secretary-General Antonio Guterres on Monday warned that the bombarded Gaza Strip was becoming a "graveyard for children," as he urged an immediate ceasefire in the Israel-Hamas conflict.

"The unfolding catastrophe makes the need for a humanitarian ceasefire more urgent with every passing hour," he told reporters at the UN headquarters in New York.

"The parties to the conflict -- and, indeed, the international community -- face an immediate and fundamental responsibility: to stop this inhuman collective suffering and dramatically expand humanitarian aid to Gaza," he said.

Nobel Peace Prize winner Narges Mohammadi has begun a hunger strike in her Iranian prison in protest at limits on medical care for her and other inmates, as well as the obligation for women to wear the hijab in the Islamic republic, her family said on Monday.

Veteran rights activist Mohammadi, 51, currently held in Tehran's Evin prison, was awarded the Nobel prize in October "for her fight against the oppression of women in Iran".

Tens of thousands of Gaza's residents live in eight refugee camps that were set up following the mass exodus of Palestinians during the war that followed the creation of Israel in May 1948.

Over 760,000 Palestinians fled or were driven from their homes in what is referred to by Palestinians as the "Nakba" (catastrophe in Arabic).

Around 180,000 fled to Gaza, with the rest scattered across the West Bank and neighbouring Arab countries, specifically Jordan, Lebanon and Syria.

With her mane of curly hair and piercing eyes Ahed Tamimi, arrested on Monday for allegedly inciting violence and terrorism, is for Palestinians and their supporters an icon of resistance to Israeli occupation.

Images of the now 22-year-old's defiance have been beamed across the world for over a decade: aged 11 brandishing her fist under the nose of Israeli soldiers, aged 14 fighting to free a detained boy, aged 16 in prisoner's clothing surrounded by Israeli police.