Hamas and Islamic Jihad announced a cease-fire late Saturday night following regional and international mediation efforts after the most serious and widespread flare-up between Israel and Palestinian fighters in Gaza since the 2014 war.

However, hours later rocket alerts sounded in two Israeli Gaza-border communities, and the Israeli military said it struck in Gaza after mortrars were fired at Israeli territory.

Footage of the IDF strike in Gaza

Two Palestinian were said to be killed by Israeli strikes and four Israelis lightly wounded after a rocket fired from Gaza struck their home in the southern city of Sderot earlier on Saturday.

Open gallery view Map of southern communities

The Israeli military struck more than 40 Hamas targets throughout the Strip over the past 24 hours and over 190 rockets and mortar shells were fired from Gaza at Israel, 100 of which were fired after 3:00 P.M. 73 projectiles struck open areas in Israel while 37 projectiles were intercepted by the Iron Dome missile defense system. More than 160 rocket alarm sirens have sounded throughout communities near the Israel-Gaza border.

14 Palestinians were wounded after the strikes, according to the Gaza Health Ministry. The wounded Israelis include a 50-year-old male with wounds to his chest, a 17-year-old female with facial wounds and a 20-year-old female with wounded limbs. Emergency responders took the wounded to Barzilai Medical Center in Ashkelon.

>> Explained: Netanyahu Resists Pressure for Gaza War, but Flames Are Getting Higher ■ Gaza flare-up: Hamas changed the rules, Israel will respond forcefully | Analysis

Prime Minister Benjamin Netanyahu said "we will expand our reaction as much as needed. If Hamas doesn't understand the message today, it will tomorrow."

Netanyahu held ongoing discussions with Defense Minister Avigdor Lieberman, IDF chief of staff Gadi Eisenkot and senior security officials: "We agreed to take decisive action against Hamas terrorism. The IDF hit Hamas with the hardest blow since Operation Protective Edge, and we will intensify the strength of the attacks if necessary."

The army is ready "for the possibility that these events will spread beyond Gaza's borders," a senior officer of Israel's air force said.

According to the officer, "the air force has the largest deployment, both on the defensive and offensive, since Operation Protective Edge in 2014," he said. "Since last night, over 90 rockets were launched at Israel, and over 20 were successfully intercepted by the air force," he added.

Open gallery view The site where a rocket landed in in Sha'ar Hanegev, Israel, Saturday, July 14, 2018 Credit: Eliyahu Hershkowitz

A Hamas spokesman said Saturday that "the escalation and intensification of Israel's aggression will not dictate a new agenda," adding that it would not "stop the procession of return. Resistance forces will not let Israel continue attacking the Palestinian people, and we will be ready to respond."

Israel's cabinet will meet on Sunday to discuss the escalation in the south. A Palestinian official who spoke to Reuters on condition of anonymity said Egypt and other international players were holding contacts with Israel and Gaza to restore calm. There was no immediate comment from officials in Cairo.

The IDF said it carried out an airstrike against a high-rise building in the Shati refugee camp in northern Gaza, which was used as a training facility for Hamas fighters.

Israel targeted 40 Hamas targets in Saturday's strikes, including two attack tunnels, logisitical centers and the organization's Beit Lahia battalion headquarters. The army said it struck the tunnels in response to Friday's incident in which an IDF officer was moderately wounded after demonstraters threw a grenade at him in northern Gaza.

Six of the 31 rockets launched overnight were intercepted by the missile defense system; one exploded near an Israeli border community. The IDF Spokesperson's Unit said 60 rockets were fired at Israel since 6:00 A.M. Saturday, 10 of which were intercepted by the Iron Dome.

The army sent messages to Hamas through an intermediary last week saying it will conduct a harsh military response against incendiary kites and balloons launched from Gaza if it continues. The army also said last week that an Israeli aircraft had fired a warning missile near a cell that had launched incendiary balloons from northern Gaza.

>> IDF warns Hamas of harsh military response if incendiary kites and balloons into Israel continue

On Saturday, a 20-year-old Palestinian died from wounds sustained in clashes during border protests Friday, bringing the death toll to two following the latest round of demonstrations, the Gaza Health Ministry reported.

Meanwhile, footage of the 15-year-old Palestinian who was killed by Israeli army fire on Friday emerged, showing him trying to climb the fence and getting shot. The two deaths bring the total toll since the beginning of the so-called "March of Return" to 139.

Reuters contributed to this report