There have been appeals for calm after days of unrest in Jerusalem spiralled into retaliatory attacks by Israel and Palestinian militants in Gaza.
The United States, European Union and United Kingdom have urged both sides to lower tensions as soon as possible.
Militants have fired more than 300 rockets towards Israel since Monday night, injuring 31 Israelis.
Israel says its air strikes on Gaza have hit 130 targets. Health officials say 24 Palestinians have been killed.
The militant group Hamas, which controls the Palestinian territory, said it was acting to defend Jerusalem’s al-Aqsa mosque from Israeli “aggression and terrorism” after the site, which is holy to Muslims and Jews, saw clashes between Israeli police and Palestinians on Monday that left hundreds injured.
Israeli Prime Minister Benjamin Netanyahu said Hamas had “crossed a red line” by firing rockets towards Jerusalem for the first time in years and that Israel would respond “with great force”.
It followed mounting Palestinian anger over the threatened eviction of families from their homes in occupied East Jerusalem by Jewish settlers, fuelled by a month of altercations between protesters and police in the predominantly Arab part of the city.
The open wound of an unresolved conflict
The fundamental reason for the renewed violence does not change. It is the open wound of the unresolved conflict between Jews and Arabs that has blighted and ended Palestinian and Israeli lives for generations.
This latest episode has happened because of tension in Jerusalem, the sharpest part of the conflict. The holy sites in the Old City are national as well as religious symbols. Crises affecting them have often ignited violence.
The triggers for what has happened this time include heavy-handed Israeli policing of Palestinians during Ramadan and controversial efforts in the Israeli courts to evict Palestinians from their homes.
But other events could have had the same effect. This was a crisis waiting to happen, in a conflict that, once again, has been left to fester.
The biggest challenge, of making peace, has not been addressed seriously for years.
What’s the latest on the ground?
The violence did not abate overnight and the sound of Palestinian rockets and Israeli air strikes echoed across the region on Tuesday morning.
At dawn, rockets hit two homes in the southern Israeli city of Ashkelon.
Israeli medics said 31 people were injured. They included a 40-year-old man who suffered head injuries and is in a serious condition in hospital. His wife and two children were also hurt.
Hamas said it had fired rockets at Ashkelon in retaliation for an Israeli strike on the home of a top commander. It also threatened to turn the city “into hell” if Palestinian civilians were targeted.
The Israeli military also said 300 had been fired and that over 90% had been intercepted by its Iron Dome missile defence system.
The Israeli military said it had struck 130 “terror targets” in Gaza overnight in response, including two attack tunnels being dug under the border with Israel, a Hamas intelligence facility, and weapons manufacturing and storage sites.
“We intend to continue to hit Hamas and all of their military components because of their blatant aggression against Israel,” spokesman Lt Col Jonathan Conricus told the BBC.
The Hamas-run health ministry in Gaza reported that at least 24 Palestinians, including nine children, had been killed in Israeli strikes and more than 100 others had been injured.
It said a 59-year-old woman and her disabled son had died in an attack on Tuesday morning.
On Monday night, seven members of one family, including three children, died in an explosion in Beit Hanoun.
The Israeli military said at least 15 of those killed had been members of militant groups and that the other deaths might have been due to Palestinian rockets falling short.
“We do whatever we can in order to use the most precise munitions against militants and militants only. But the situation is almost impossible on the ground. Hamas and other terrorist organisations are embedding themselves within the civilian population,” Lt Col Conricus said.
What’s the global reaction?
US Secretary of State Antony Blinken said Hamas must end the rocket attacks “immediately”, adding: “All sides need to de-escalate.”
White House spokeswoman Jen Psaki echoed those calls, saying US President Joe Biden was seriously concerned about the violence.
In a tweet, UK Foreign Secretary Dominic Raab said the rocket attacks “must stop”, calling for “an end to targeting of civilian populations”.
A spokesman for the EU’s foreign policy chief, Josep Borrell, said the “significant upsurge in violence” in the West Bank, Gaza and East Jerusalem “needs to stop immediately”.
“The firing of rockets from Gaza against civilian populations in Israel is totally unacceptable and feeds escalatory dynamics,” the spokesman added.
A spokesperson for the Office of the UN High Commissioner for Human Rights, Rupert Colville, said it was “deeply concerned” by the escalation and condemned “all incitement to violence and ethnic division and provocations”.
The UN Security Council held an urgent meeting on Monday to discuss the situation but did not issue a statement.
A Palestinian official told Reuters news agency that the UN, Egypt and Qatar, which often mediate between Israel and Hamas, were all trying to halt the fighting.
What has caused the violence?
The fighting between Israel and Hamas was triggered by days of escalating clashes between Palestinians and Israeli police at a holy hilltop compound in East Jerusalem.
The site is revered by both Muslims, who call it the Haram al-Sharif (Noble Sanctuary), and Jews, for whom it is known as the Temple Mount. Hamas demanded Israel remove police from there and the nearby predominantly Arab district of Sheikh Jarrah, where Palestinian families face eviction by Jewish settlers. Hamas launched rockets when its ultimatum went unheeded.
Palestinian anger had already been stoked by weeks of rising tension in East Jerusalem, inflamed by a series of confrontations with police since the start of the Islamic holy month of Ramadan in mid-April. It was further fuelled by an expected court ruling on the fate of the families in Sheikh Jarrah – ultimately postponed because of the unrest – and Israel’s annual celebration on Monday of its capture of East Jerusalem in the 1967 Middle East war, known as Jerusalem Day.
The fate of the city, with its deep religious and national significance to both sides, lies at the heart of the decades-old Israel-Palestinian conflict. Israel in effect annexed East Jerusalem in 1980 and considers the entire city its capital, though this is not recognised by the vast majority of other countries. Palestinians claim the eastern half of Jerusalem as the capital of a hoped-for state of their own.