In a highly irregular move, the Israel Defense Forces launched a series of retaliatory airstrikes on Palestinian Islamic Jihad sites in both Syria and the Gaza Strip on Sunday night in response to waves of rocket attacks by the Iran-backed terror group throughout the evening, the military said.

“IDF fighter jets struck terror sites belonging to the PIJ terror group south of Damascus in Syria, as well as dozens of PIJ sites throughout the Gaza Strip,” the IDF said in a statement.

Islamic Jihad said in a statement that the airstrikes killed two of its members, identifying them as Salim Salim, 24, and Ziad Mansour, 23. It did not disclose their nationalities or elaborate on their roles. The militant group vowed to respond to the deaths of its members.

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Israel rarely acknowledges conducting airstrikes in Syria, save for those that are in retaliation to attacks coming from there.

Rocket attacks against southern Israel continued throughout the IDF’s counter-attack, triggering several rounds of sirens in the town of Sderot and the surrounding area.

Throughout Sunday evening, some 30 rockets and mortar shells were fired at southern Israel from the Gaza Strip, approximately half of which were intercepted by the Iron Dome missile defense system.

The rocket fire came after an irregular clash along the Gaza border earlier in the day in which Israeli troops shot dead a member Palestinian Islamic Jihad as he planted an improvised explosive device along the border. The Israeli military then retrieved his body, using a bulldozer.

The IDF said the strikes in Syria and Gaza were in response to both the morning’s attempted IED attack and the rocket fire throughout the evening.

“The IDF will respond aggressively to the terrorist activities of the Islamic Jihad, which endanger the citizens of Israel and harm its sovereignty,” the military said.

The IDF said its fighter jets targeted the main base of the Iran-backed terror group in Syria, which it said was used to develop new weapons and to manufacture “tens of kilograms of [ammonium perchlorate]” rocket fuel each month.

The military said the site, in the Damascus suburb of al-Adleyeh, was also used for training exercises for members of the organization “both from the Strip and on the northern front,” referring to Lebanon and Syria.

Syrian state media outlet SANA reported that the incoming Israeli attacks triggered the country’s air defenses, which it said intercepted many of the incoming missiles, an oft-heard Syrian claim that most defense analysts dismiss as a false boast.

In addition to the strikes outside Damascus, the IDF bombed several Islamic Jihad sites in the Gaza Strip. The military said one of its aircraft also targeted a group of Islamic Jihad members preparing to launch rockets from the northern Gaza Strip and that “a hit was identified.” The Hamas-run Gaza health ministry reported that four people were injured in the strike.

The IDF confirmed reports in Palestinian media that it struck military bases and weapons depots belonging to the terror group in Beit Lahiya, Rafah and Khan Younis.

The military first bombed an Islamic Jihad’s military base in Beit Lahiya in northern Gaza.

“In Rafah, underground facilities and depots for storing rocket manufacturing ingredients were attacked,” the IDF said.

Palestinian media reported that two Palestinians were injured in this strike, with the Israeli Air Force firing at least 18 missiles at the site, completely destroying it.

In Khan Younis, the IDF said it struck an Islamic Jihad command center, which contained an anti-tank guided missile training center and military equipment used by the group’s naval commandos.

In light of the exchange of fire on Sunday night, the IDF Home Front Command ordered schools to close Monday in the communities closest to the Gaza Strip, including the cities of Ashkelon, Sderot, and Netivot. Large outdoor gatherings were also forbidden, and residents of the area were only permitted to go to work if they were in close proximity to a bomb shelter.

In announcing the start of its airstrikes on Islamic Jihad targets, the IDF notably did not mention the Gaza-ruling Hamas terror group, with which Israel hopes to negotiate a ceasefire agreement. In the past, Israel held Hamas responsible for all violence emanating from the Strip, regardless of which terror group was behind it. However, the IDF has increasingly differentiated between Hamas and the Islamic Jihad, which Israel believes is responsible for the majority of the violence along the Gaza border in recent months.

In November, Israel fought a punishing two-day battle with the Islamic Jihad, sparked by the IDF killing one of the terror group’s leaders — Baha Abu al-Ata — whom Israel believed was responsible for most of the group’s aggressive actions.

During that round of fighting, the IDF reportedly targeted one of the group’s senior leaders — Akram al-Ajouri — who lives in Syria, but missed him.

Islamic Jihad took responsibility for Sunday’s rocket attacks, writing on its website that it fired the rockets in response to Israel taking the terrorist operative’s corpse earlier in the day.

The rocket fire on southern Israel did not cause any injuries.

The projectiles that were not intercepted by the Iron Dome apparently struck open fields in unpopulated areas, causing neither injuries nor damage.

In at least three cases, shrapnel from interceptions over populated areas caused light property damage — to a garden in the Sha’ar Hanegev region, to a car in the city of Ashkelon and to a home in the town of Sderot.

Prime Minister Benjamin Netanyahu, Defense Minister Naftali Bennett and senior members of Israel’s security services met in the military’s Kirya headquarters in Tel Aviv on Sunday night to discuss both a response to the attack and the situation in the Gaza Strip in general.

Islamic Jihad’s first bombardment, shortly after 5:30 p.m., triggered multiple rounds of sirens on Sunday evening in the cities of Ashkelon and Sderot and in smaller Israeli communities in the area around the Strip known as the Gaza periphery.

The local councils for the Eshkol, Sha’ar Hanegev and Hof Ashkelon regions, as well as the Magen David Adom ambulance service, said they received no reports of direct injuries or damage caused by the rocket fire.

The second wave of rocket fire, at around 8 p.m., was directed toward the city of Ashkelon and the Eshkol region.

An Eshkol spokesperson said the projectiles fired at the region appeared to have landed in open fields outside the community of Kissufim.

A piece of shrapnel from an Iron Dome interception appeared to have struck an empty, parked car in the city of Ashkelon, damaging the vehicle, but causing no injuries.

At 9 p.m., a third round of sirens sounded in Sderot and the surrounding communities, sending thousands of Israelis rushing to bomb shelters. At least one Iron Dome missile was launched amid the sirens, with residents of the area seeing a mid-air explosion, possibly indicating an interception.

Shrapnel from the missile caused light damage to a home in Sderot, but no injuries, a municipal spokesperson said.

Fifteen minutes later, a rocket was fired toward Kibbutz Nahal Oz, just east of Gaza, which struck an open field outside the community, a spokesperson for the Sha’ar Hanegev region said.

Following the first attack, the city of Ashkelon said it was opening all of its public bomb shelters and preemptively canceling school on Monday. The Southern Police District also announced it was bringing in additional officers to the area in case the rocket fire continued.

Earlier on Sunday, the Hamas and Palestinian Islamic Jihad terror groups denounced Israel for retrieving the body of the alleged bomb-planter.

The Islamic Jihad threatened that “the blood of martyrs will not be in vain.” Hamas spokesman Fawzi Barhoum said the “maltreatment” of the corpse was “another heinous crime that has been added to its record of awful crimes at the expense of our Palestinian people.”

According to the IDF, two Islamic Jihad operatives planted an improvised explosive device along the Gaza security fence east of the city of Khan Younis in the early hours of Sunday morning. The military released surveillance camera footage showing the men placing an object next to the fence and said they were members of an Islamic Jihad cell that had planted at least two other explosive devices along the border in recent months.

IDF troops on the scene opened fire on the two men, killing one and critically wounding the second, according to Palestinian media. The fatality was later identified as Muhammad al-Na’im, 27.

Shortly after the clash, an Israeli armored bulldozer entered the buffer zone surrounding the Gaza Strip and lifted up the mangled body, carrying it back toward Israel, as a group of Palestinian men pelted the heavy engineering vehicle with stones, according to graphic video footage shared on social media.

As the men attacked the bulldozer, which was guarded by a Merkava tank, a gunshot could be heard and several of the men began hopping away. Palestinian media reported that four people in total were injured by the Israeli gunfire. The Hamas-run Gaza health ministry confirmed that at least two men were shot by Israeli troops and sustained injuries to their legs.

The Palestinian Islamic Jihad terror group’s military wing, the al-Quds Brigades, acknowledged that at least one of them was a member of the organization, identifying him as Na’im. The al-Quds Brigades did not specify if the second man was a member of the terror group.

The retrieval of the corpse was part of Defense Minister Bennett’s plan to “hoard” the corpses of Palestinian terrorists in order to use them as “bargaining chips” in negotiations for the release of two Israeli men, and the remains of two fallen Israeli soldiers, who are being held by Hamas in the Gaza Strip.

“We are hoarding the corpses of terrorists in order to put pressure on the other side,” Bennett said in an interview on the 103 FM radio station last week.

The border clashes come amid reports of ongoing efforts by Israel to broker a ceasefire agreement with Gaza terror groups, following weeks of intermittent rocket fire and the regular launching of balloon-borne explosive devices into Israel.

Palestinian terrorists in the Gaza Strip began sending clusters of balloons and kites into Israel laden with explosives beginning in 2018. The practice has waxed and waned over that time, but has picked up considerably in recent weeks, with dozens of such balloon-borne bombs landing in towns and farming communities adjacent to the Palestinian enclave.

On February 5, the military restricted Gaza’s permitted fishing zone down to 10 nautical miles and canceled some 500 travel permits after weeks of regular rocket fire and the launching of balloon-borne explosive devices into Israel from Gaza.

Last Tuesday, Israel said it would extend the fishing zone back to 15 nautical miles and increase the number of travel permits from the Strip to 2,000, following three days of relative calm in the coastal enclave. It said those eased restrictions would continue only if calm remains.

At the same time, Netanyahu said the military was planning a “big surprise” for Hamas if the terror group failed to rein in violence aimed at southern Israel, amid reports that Israel was contemplating the assassination of two senior Hamas leaders.

The prime minister said he would not subject any decision on Gaza to “political timetables,” referring to the upcoming March 2 election, adding that he would “choose the right time to take action.”

The London-based pan-Arab website Al-Araby Al-Jadeed reported last week that an Egyptian intelligence delegation that visited the Gaza Strip did so after receiving information that Israel was planning to assassinate two prominent Hamas figures.

The website said it had been told by sources that Cairo had persuaded Israel to suspend a decision to assassinate Yahya Sinwar, the leader of Hamas in the Gaza Strip, and Marwan Issa, the leader of its military wing, the Izz ad-Din al-Qassam Brigades.

On Saturday night, Yisrael Beytenu party chief Avigdor Liberman revealed that Mossad chief Yossi Cohen and the head of the IDF Southern Command, Maj. Gen. Herzi Halevi, had visited Qatar earlier this month to plead with its leaders to continue their periodical payments to Hamas in order to help maintain calm in the restive Palestinian enclave.

Times of Israel staff and agencies contributed to this report.