Two pregnant women and two babies in Gaza are among the dead after a fresh round of violence between Israel and Palestinian militants.
Hundreds of rockets were fired into southern Israel on Sunday, killing at least four Israelis in the bloodiest fighting since the weeks-long 2014 war.
The number of Palestinians who died rose to 23, including two expectant mothers and two babies.
Israel claim militants fired over 600 rockets into the country by Sunday, with most falling into open landscape or being blocked by the Iron Dome rocket-defence system. However, more than 30 hit urban areas, according to the Israeli army.
Those killed in Israel include Moshe Agadi, a 58-year-old Israeli father of four, who was fatally struck in the chest by shrapnel in a residential courtyard, a 49-year-old man killed when a rocket hit a factory and two men whose vehicles were hit by two separate missiles.
These are the first Israeli rocket-related deaths since 2014.
Israeli police said 66 people were wounded, with three in a serious condition. The military said it hit 250 targets in Gaza, including weapons storage and rocket launching facilities.
Across the border, Palestinian medical officials reported 23 dead, including at least eight militants hit in targeted airstrikes.
The Palestinians said a 37-year-old pregnant woman and her 14-month-old niece were killed in an Israeli airstrike. Israel denied this, saying they were hit by a stray Palestinian rocket.
An Israeli airstrike hit an apartment building in northern Gaza. A couple in their early 30s and their four-month-old daughter died.
A 12-year-old boy was also killed in northern Gaza.
Despite calls by the UN Middle East envoy calling for a ceasefire, the fighting shows no signs of relenting yet.
Israeli Prime Minister Benjamin Netanyahu, who recently survived a tight election, spent most of Sunday locked in talks with his security cabinet, which instructed the army to “continue its attacks and to stand by” for further orders.
Israel claims to have killed a Hamas commander they say was involved in transferring Iranian funds to the group.
Hamas leader Ismail Haniyeh said in a statement released late on Sunday that the militant group was “not interested in a new war”.
He indicated he was ready to “return to the state of calm” if Israel stopped its attacks “and immediately starts implementing understandings about a dignified life”.
US President Donald Trump weighed in, directly addressing those in Gaza and accusing them of being terrorists.
He tweeted: “Once again, Israel faces a barrage of deadly rocket attacks by terrorist groups Hamas and Islamic Jihad. We support Israel 100% in its defence of its citizens….
“….To the Gazan people – these terrorist acts against Israel will bring you nothing but more misery. END the violence and work towards peace – it can happen!”
In more measured comments, US secretary of state Mike Pompeo said Israelis have “every right to defend themselves” but added that he hoped the recent ceasefire could be restored.
EU foreign policy chief Federica Mogherini called for “indiscriminate rocket attacks” from Gaza to stop and expressed support for mediation efforts.
This week Israel will mark Memorial Day, one of the most solemn days of the year for the country, and its Independence Day.
The following week, Israel is set to host the Eurovision song contest. Ongoing fighting may prompt tourists and visitors to stay away.