Israel and Islamic Jihad militants on Sunday began a precarious Egyptian-brokered truce hoped to end three days of conflict in Gaza that has left at least 44 Palestinians dead, including 15 children.
The truce, which officially started at 11.30pm local time, aimed to stem the worst fighting in Gaza since an 11-day war last year devastated the Palestinian coastal territory.
That conflict claimed 250 lives, and there were fears that the current fighting could worsen to similar destruction.
A series of strikes and rocket attacks took place in the lead-up to the truce, with sirens sounding in southern Israel moments before and after the deadline.
Three minutes after the ceasefire began, Israel's army said that "in response to rockets fired toward Israeli territory, the [military] is currently striking a wide range of targets" belonging to Islamic Jihad in Gaza.
The army later said its "last" strikes took place at 11.25pm.
"The situation is still very fragile and I urge all parties to observe the ceasefire," UN Middle East peace envoy Tor Wennesland said.
"If the ceasefire is violated, the state of Israel maintains the right to respond strongly."
Senior Islamic Jihad member Mohammad Al Hindi said: "A short while ago the wording of the Egyptian truce agreement was reached."
The militant movement said it "reserves the right to respond to any Zionist aggression".
Israel's military said it had "neutralised" the leadership of Islamic Jihad in Gaza, where at least 32 people, including six children, have been killed in three days of Israeli strikes on the Palestinian territory.
Islamic Jihad has responded by firing hundreds of rockets into Israel without causing major casualties or damage.
The Israeli military said it was continuing its attacks on Sunday with strikes on the militant group's tunnels, while Islamic Jihad fired rockets towards Jerusalem for the first time during the latest conflict.
Gaza's Health Ministry overnight raised the death toll to 44 including 15 children, with more than 300 people wounded in the Palestinian enclave, which is run by the Islamist group Hamas.
Three people in Israel have been wounded by shrapnel over the same period, while 31 others have been slightly injured, emergency services said on Sunday.
Gaza's top hospital director Muhammad Abu Salmiyav issued a warning on Sunday that medicine and electricity supplies were urgently needed to keep treating patients.
Israel said it had "irrefutable" evidence that some of the children were killed when a rocket fired by Islamic Jihad landed in the Jabaliya area in northern Gaza on Saturday.
The military shared a video on its Twitter account that appeared to show a rocket falling to earth shortly after launch.
Israel's military earlier said its aerial and artillery campaign against Islamic Jihad could last a week.
But Egypt's President, Abdel Fattah El Sisi, said Cairo was talking "around the clock" with both sides to ease the violence. The Israeli government also confirmed on Sunday that it was in talks with Egypt.
The UAE, China, France, Ireland and Norway requested a closed meeting of the UN Security Council on Monday to discuss the developments in Gaza, state news agency Wam reported, quoting an official at the Ministry for Foreign Affairs and International Co-operation.
"The United Arab Emirates has emphasised the need to restore calm to the Gaza Strip, reduce escalation and preserve civilian lives," Wam reported Afra Al Hameli, spokeswoman for the ministry, as saying.
Israel said it was necessary to launch a "pre-emptive" operation against Islamic Jihad, because the group was planning an attack after days of tension along the border with Gaza.
The head of the army's operations directorate, Oded Basiok, said the entire "senior leadership of the military wing of the Islamic Jihad in Gaza has been neutralised".
Islamic Jihad has confirmed the deaths of Tayseer Al Jabari, a senior commander, in an air strike in Gaza city on Friday, and of Khalid Mansour, commander of its southern Gaza division, in a strike in Rafah on Saturday.
Eight people were killed in the Rafah strike, including a 14-year-old, Gaza's Interior Ministry reported.
With injuries mounting, Gaza's Health Ministry warned that vital services could be suspended within 72 hours after the territory's only power plant shut down on Saturday.
An electricity company spokesman said the plant had run out of fuel after Israel blocked the entry of all goods into Gaza earlier in the week.
The exchange of fire brought life to a standstill in Gaza and forced civilians in southern and central Israel into air-raid shelters since Friday.
Israel's Magen David Adom emergency service said two people were taken to hospital with shrapnel wounds and 13 others were slightly hurt while running for safety.
In Kibbutz Nahal Oz, an Israeli community beside the Gaza border, resident Nadav Peretz, 40, said he had been "in the bomb shelter or around it" since Friday.
"We recognise that on the other side too there is an uninvolved civilian population, and on both sides children deserve to enjoy their summer vacation," Mr Peretz said.
Islamic Jihad is aligned with Hamas but often acts independently. Both are listed as terrorist organisations by much of the West.
Hamas has fought four wars with Israel since seizing control of Gaza in 2007, including the conflict last May.
A flare-up with Islamic Jihad came in 2019, after Israel killed Baha Abu Al Ata, Al Jabari's predecessor. Hamas did not join that conflict.
Hamas's moves now could prove crucial, with the group facing pressure from some to restore calm to improve economic conditions in Gaza.
Focus will in part turn to Jerusalem on Sunday, where some Jews will mark the Tisha Be'av remembrance day by visiting Islam's third most important site, Al Aqsa Mosque compound, in Israel-annexed East Jerusalem.
Tension at the compound, which is also sacred to Jews, have previously sparked wider violence.
Hamas's chief, Ismail Haniyeh, issued a warning against allowing Jews to "storm" the compound on Sunday, saying it could lead to an "uncontrollable" security crisis given the events in Gaza.
Extreme-right Israeli politician Itamar Ben Gvir was scheduled to visit the compound on Sunday morning.
With reporting from agencies.