Rockets fired by Palestinian militants are seen over the Gaza Strip heading toward Israel, early Wednesday. (Hatem Moussa/AP)

An unofficial cease-fire took hold Wednesday in the Gaza Strip and southern Israel after the worst outbreak of fighting since a 2014 war between Israel and Hamas, the militant Islamist group that rules the beleaguered Palestinian enclave.

During a 24-hour flare-up, militant factions in Gaza, including Hamas, fired more than 100 rockets and mortar shells into Israel starting Tuesday and continuing through Wednesday morning. Israeli jets pounded more than 50 military targets belonging to Hamas and Islamic Jihad in response. 

Israel said some of the rockets fired into its territory were Iranian-made. Although the Iron Dome defense system downed most of the rockets, one hit a civilian home and another a kindergarten. 

However, by early Wednesday, spokesmen for Hamas and Islamic Jihad said that a cease-fire with Israel had been brokered by Egypt.

Khalil al-Hayya, a senior Hamas official, said that “there was a lot of mediation in the past hours.” He said the factions, including Islamic Jihad, would uphold the cease-fire as long as Israel did the same. 

Israeli leaders would not confirm that an agreement was reached, although local media reported that Hamas had received a message that if the rockets from Gaza stopped, Israel’s airstrikes would, too.

Israeli officials believe that Hamas, under pressure from outside players, has decided to return to restraint and rein in some of the more extreme factions that operate in the strip.

 In an interview with Israeli radio, Education Minister Naftali Bennett denied that any deal was reached with Hamas.

“There are no understandings,” Bennett said.  It is up to the other side to “decide its fate, but we did not reach any agreements with Hamas,” he added. “We take action in keeping with Israel’s interests.”

There has been widespread speculation in Israel and Gaza of discussions on a wider peace agreement between the two sides, as tensions have soared over the past few months. 

“This latest escalation was actually initiated by the Islamic Jihad and not Hamas, partly because there has been progress in reaching an understanding between Hamas and Israel,” said Kobi Michael, a senior researcher at Israel’s Institute for National Security Studies and former deputy director general at the Ministry of Strategic Affairs.

Michael said he believed there may have been overtures in recent weeks between the two sides, possibly facilitated by Egypt and Qatar. 

“Palestinian Islamic Jihad is a pure Iranian proxy and a very militant organization. Unlike Hamas, they do not have any responsibility to the civilians in Gaza,” he said. “They do not want to see any progress to be made between Hamas and Israel because it works against their ideology.” 

Michael said Hamas was in a difficult position following weekly mass demonstrations at the Israel-Gaza border fence. Israeli forces have killed more than 100 people in those protests, including 60 on May 14. 

Israel unilaterally withdrew from Gaza in 2005. But after Hamas took control of the strip more than a decade ago, Israel imposed a land and sea blockade on the enclave. Egypt also has kept its crossing into Gaza closed for much of the past 10 years. 

A growing humanitarian crisis in Gaza has pushed its residents to start protesting. In late March, thousands began weekly protests demanding both a right to return to land that is now inside Israel and a solution to the crisis facing more than 2 million residents. 

“They sacrificed too much and achieved very little,” Michael said. “They’ve been pressured by the Egyptians and their own civilians to reach a long cease-fire with Israel.”

Mukhaimer Abu Saada, a professor of political science at Gaza’s al-Azhar University, chalked up the renewal of hostilities to dissatisfaction among Hamas and Islamic Jihad over the current situation, which has included continued Israeli shelling.

“Even during the protests, there was shelling,” he said, even though the protests were peaceful. Abu Saada warned that the situation could further deteriorate, saying, “There has still been no declaration of war, but the possibility exists.”

Abu Saada said containment is possible if Egypt and the United Nations step in.

The U.N. special coordinator for the Middle East peace process, Nickolay Mladenov, urged calm on both sides in a statement released Tuesday. 

“Such attacks are unacceptable and undermine the serious efforts by the international community to improve the situation in Gaza,” he said. 

Itamar Yaar, former deputy head of Israel’s National Security Council, said it was unlikely that the latest escalation would lead to another war, mainly because neither side is interested in such a confrontation. He added, “Of course, things could change.”

“I think that the security establishment has given political leaders enough information for all to realize that getting rid of Hamas means reoccupying Gaza. I don’t think serious people in Israel want to reoccupy Gaza,” Yaar said. 

In southern Israel, residents spent much of Tuesday and overnight Wednesday in bomb shelters during what they said was the biggest round of rocket fire since the 2014 summer war.  

The Israeli military said in a statement Wednesday that its fighter jets had targeted sheds used to store drones, a rocket-manufacturing workshop, advanced naval weaponry, military compounds, training facilities and a munitions manufacturing site. 

“The army views the terror activity carried out by the Hamas terror organization with great severity and will continue to operate in a powerful and determined manner. The army is prepared to carry out its missions as necessary, using the variety of tools at its disposal,” the military said. 

Prime Minister Benjamin Netanyahu said the military had “hit dozens of terror targets, delivering the hardest blow in years.”

“The Hamas regime, Islamic Jihad and the other terrorist organizations, inspired by Iran, are responsible for the escalation,” Netanyahu said. “I will not detail our plans because I do not want the enemy to know what is in store. But one thing must be made clear: When they test us, they pay. And if they continue to try us, they will pay dearly.” 

Israeli authorities reported that rockets had damaged communities near the Gaza border, including a direct hit on a residence and another in the town of Netivot. In the initial barrage Tuesday morning, a rocket hit a kindergarten, although no children were inside. Local hospitals also reported several light injuries, mainly caused by shrapnel, and one Israeli soldier was in moderate condition. 

“This is something we cannot tolerate,” Lt. Col. Jonathan Conricus, an Israeli army spokesman, said at a news briefing Tuesday. “Hamas is turning the fence into an active combat zone, and we cannot tolerate attacks on Israeli civilians and military targets.” 

Among the targets hit by Israel in Gaza on Tuesday, he said, was a tunnel built to attack Israel. Conricus said the tunnel was unusual in that it snaked under Gaza’s southern border into Egypt’s Sinai Peninsula and then made a U-turn back into Israel. He said it was the 10th tunnel discovered and destroyed by Israel since October.

Hazem Balousha in Gaza City contributed to this report.