At least 50 rockets were fired from the Gaza Strip into Israel after an Israeli air strike targeted and killed an elderly Islamic Jihad commander in Gaza early Tuesday in the most severe escalation of violence in months.
In Northern Gaza The Israeli strike killed Bahaa Abu el-Atta and his wife, as Islamic Jihad promised further revenge.
Israeli Prime Minister Benjamin Netanyahu said in a live statement on Tuesday that Abu el-Atta was the main memory of many recent attacks on Israel and a "ticking bomb."
Less than two hours after the strike, sirens in central and southern Israel heard warning of incoming rockets from Gaza. The Israeli military said its "Iron Dome" air defense had captured about 20 rockets. The military released images of a rocket that hit an Israeli highway and narrowly missed two cars. Schools and businesses were closed over southern Israel.
"The barrage of rockets fired by Islamic Jihad #Gaza against Israeli civilians following our surgical strike against their commander shows exactly why he was targeted in the first place," the Israeli Defense Forces said on Twitter .
Throughout the day, Israeli jet aircraft targeted additional Islamic Jihad locations in Gaza, including a training facility and underground weapons production and storage areas, the military said. The Israeli Air Force also said it killed two fighters from the organization's rocket launch unit.
Islamic Jihad said that Abu el-Atta, 42, underwent "a heroic act" when he was murdered.
In a statement, the militant group said: "These terrorist crimes are aggression and a declaration of war against the Palestinian people, and the enemy bears full responsibility for them."
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Islamic Jihad is the second largest militant group in Gaza and is supported by Iran. That and Hamas, which runs Gaza, promises to destroy Israel and is considered terrorist groups by the United States
A Hamas spokesman warned that Israel's actions could provoke more violence.
"The Zionist enemy's assassination of leader Mujahid Bahaa Abu al-Atta is a dangerous escalation, and the continuation of the series of aggression and crime against our people and its violent resistance," said Fawzi Barhoum.
In a sign that it may want to reduce the potential for a major conflict, Israel, which usually holds Hamas responsible for Gaza, has avoided hitting Hamas targets or even mentioning the name at the organization in briefings.
"Hamas is not interested in being drawn into wars by Islamic Jihad or Israel. I think we can see a lot in the fact that they are not participating yet, nor are they stricken by Israel," said Assaf Orion, a senior researcher at the Institute for National Security Studies and a brigadier general in the reserve.
Hanan Ashrawi, a member of the PLO's Executive Committee on the West Bank, called the targeted killing of Abu el-Atta "reckless and criminal."
The Israeli airstrike coincided with an attempt to separate attack against another Islamic Jihad leader, Akram Al-Ajouri, in Damascus. Syrian state media said Israel was behind the attack. Al-Ajouri survived, but Islamic Jihad claimed the attack killed one of his sons.
An Associated Press reporter at the scene said the attack destroyed a three-story building in Damascus, located on a highway about 50 meters across the Lebanese embassy.
In his statement, Netanyahu appealed to the Israeli public for patience, saying the operation could take time.
"Israel is not interested in escalation, but we will do whatever it takes to protect ourselves," Netanyahu said.
Lt. Colonel Jonathan Conricus, a military spokesman, told reporters that Abu el-Atta was responsible for a number of new rocket attacks against southern Israel and claimed that he was actively planning new attacks.
"In the last week, we have been essentially waiting for the favorable moment to conduct the surgical strike," he said.
Conricus added that the aerial attack had been carried out with a war plane that destroyed only the floor of the building where Abu el-Atta was hiding to minimize "security damage."  Israel pulled out of Gaza in 2005 but held it under blockade, citing security concerns, Auxiliary officials warn that the 2 million Palestinians living in the narrow strip are facing an imminent humanitarian collapse.
Netanyahu is currently Israel's Deputy Prime Minister. is now trying to form a coalition government after Netanyahu failed to do so after an election in September.
The attacks will also come at a tense moment for Islamic Jihad's Iranian protectors, who are fighting under devastating US sanctions.
Iran's regional influence is also being challenged by outstanding, economically driven mass protests in Iraq and Lebanon – two countries where Tehran has great influence. The protests raise fears that Tehran fears would return to Iran-backed proxy militias in these countries. Supreme Leader Ayatollah Ali Khamenei has accused the United States and its regional allies of fighting the unrest in Iraq and Lebanon.
Associated Press contributed.