- Video report by ITV News Correspondent Martha Fairlie
At least 22 Palestinians and four Israelis have been killed as the two sides shower each other with airstrikes and rockets as violence and tensions increase in the region.
Palestinian militants in the Gaza Strip have intensified a wave of rocket fire into southern Israel, striking towns and cities across the region, killing at least four people, in the first Israeli rocket-related fatalities since the 2014 war.
Meanwhile at least 22 Palestinians, including two pregnant women, a 14-month-old girl and a 12-year-old boy, have been killed in Israeli airstrikes.
Eight of the Palestinian dead are said to have been militants.
Israel claimed the death of Falistin Abu Arar, 37, and her 14-month-old niece, Seba Abu Arar, who were both killed on Saturday, were caused by a misfiring Palestinian rocket.
More than 100 people have been injured on both sides.
The deaths mark one of the bloodiest rounds of fighting since the 2014 war and comes just one month after a truce.
As rockets were fired into southern Israel from Gaza, Israeli forces struck dozens of targets throughout the region, including militant sites that it claimed were concealed in homes or residential areas.
More than 600 rockets have been fired from across the weekend, while the Israeli ministry retaliated with at least 260 airstrikes.
The fighting came as leaders from Hamas, the militant group that rules Gaza, and the smaller armed faction Islamic Jihad, were in Cairo for talks with Egyptian mediators aimed at preventing a fraying ceasefire from collapsing.
The truce had seen Israel agree to ease a crippling blockade on Gaza in exchange for a halt in rocket fire.
The leader of Hamas says his group is "not interested in a new war" with Israel.
Ismail Haniyeh said in a statement late on Sunday that the militant group is ready to "return to the state of calm" if Israel stops its attacks "and immediately starts implementing understandings about a dignified life."
The latest violence comes at a sensitive time for Israel, which is to mark its Memorial Day and Independence Day holiday this week, before hosting the Eurovision Song Contest in the middle of the month.
Heavy fighting could overshadow Eurovision and potentially deter international travellers from attending.
For Gazans, the violence comes ahead of the Muslim holy fasting month of Ramadan that begins Monday.
Israel and Hamas, an Islamic group that opposes Israel’s existence, have fought three wars and dozens of smaller flare-ups of violence since Hamas seized control of Gaza in 2007.
They engaged in several days of heavy fighting in March before Egypt brokered a truce in which Israel agreed to ease a crippling blockade on Gaza in exchange for a halt in rocket fire.
In recent days, Hamas accused Israel of reneging on its pledges as militants began to fire rockets into Israel.
An Israeli military spokesperson, Lieutenant Colonel Jonathan Conricus claimed his country's strikes hit a variety of "high-quality" militant sites, that included commanders' homes in which militant activity was observed.
He said he had no knowledge of civilians being harmed by Israeli fire.
He continued that Israel was deploying an armored brigade along the Gaza front, with tanks ready for offensive missions as needed.
Israeli Prime Minister Benjamin Netanyahu said Hamas was paying a "heavy price" for its rocket attacks against Israel and that it would be held accountable not only for its own militant actions but also for that of the Islamic Jihad, which operates under its jurisdiction in Gaza.
Sirens wailed along the border region overnight and throughout Sunday warning of incoming attacks.
School was canceled in southern Israel and emergency protocol enacted.
In Gaza, large explosions thundered across the blockaded enclave during the night as plumes of smoke rose into the air.
By morning, bulldozers were clearing the streets from rubble and debris strewn on the ground and municipal workers were fixing damaged power lines.
Despite claims by Israel it was only targeting "militant sites", one of its many airstrikes hit a six-story commercial and residential building that housed the office of Turkey's official Anadolu news agency.
Turkish Foreign Minister Mevlut Cavusoglu called it a "new example of Israel's unrestrained aggression".
"We thought the Rimal neighborhood is safe, but it seems there is no safe place in Gaza," said Nidal al-Dali, who lived in the building and lost his home.
The Israeli military says its Iron Dome defence system intercepted more than 150 of the projectiles from Gaza, but several still managed to slip through.
A rocket scored a direct hit on a residential home in the border town of Sderot.
Meanwhile the Barzilai Medical Center in Ashkelon - which has treated some 110 people, most from shock symptoms, but several with body wounds - was hit by debris from a rocket that was intercepted by an Iron Dome missile. There were no injuries.
The latest round of violence began on Friday when two Israeli soldiers were shot and wounded on Friday.
On the same day, two Palestinians were shot dead by Israeli forces during the weekly protests along the Israel-Gaza perimeter fence which aim to draw attention to Gaza's plight and highlight the blockade which has ravaged Gaza's economy.
More than 200 Palestinians and an Israeli soldier have been killed in the border protests which have been taking place for more than a year.
Yaakov Amidror, a former Israeli national security adviser, alleged the violence was being instigated by Islamic Jihad militants in Gaza at the behest of their backers in Iran.
Mr Amidror, currently a senior fellow at the Jerusalem Institute for Strategy and Security, claimed a new war in Gaza would distract Israel and leave Tehran "free to continue what they are doing in Syria".