By Nidal al-Mughrabi and James Mackenzie
GAZA/JERUSALEM (Reuters) - Israel's latest round of airstrikes against Palestinian militants in the Gaza Strip left familiar images of towering spirals of smoke and wailing sirens but none of the buildings left in rubble by the jets belonged to its main enemy, Hamas.
Instead, the strikes targeted the Iranian-backed Palestinian Islamic Jihad, killing six senior commanders who Israel said had planned and carried out attacks on Israelis, and destroying dozens of rocket silos, mortars and tunnels across Gaza.
But while Islamic Jihad fired hundreds of rockets at Israel in response, Hamas - with a rocket arsenal estimated at four times the size - stayed on the sidelines, apparently unwilling to see a repeat of the fierce 10-day conflict it fought in May 2021.
"It is not that Hamas is afraid of confrontation with Israel, it is rather not willing to have a large-scale war so soon," said a regional diplomat, who has long experience working with Hamas officials.
The diplomat, who was involved in the talks that brought a ceasefire to last week's flare up, spoke on condition of anonymity because of the sensitivity of the matter.
Israel's decision to avoid targeting the most powerful Palestinian faction with which it has fought repeated wars in the past decade, points to the complexity of the relationship with a group that has run Gaza since 2007, even though Israeli officials insist the military could strike Hamas at any time.
The two sides may be sworn enemies, but they share an interest in maintaining a basic level of stability in Gaza, where 2.3 million people live in a coastal enclave of just 365 square kilometres between Israel and Egypt.
Israel maintains a strict blockade, yet almost 20,000 Gazans are allowed to leave the enclave to work in Israel or the West Bank in jobs that provide about $3 million a day in wages to a territory where around half the population is out of work.
Prime Minister Benjamin Netanyahu alluded to Israel's calculations at work in dealing with Hamas in Gaza.
"Hamas, like other extremist Islamist movements, flies the banner of destroying Israel, so it is very difficult to achieve real accords with them," he said this week. "But are there certain areas in which to maneuver here? The answer is that, when deterrence is strong, such areas grow accordingly."
Michael Milshtein, a former official of COGAT, the office that coordinates Israeli governance over the West Bank said there was a form of tacit agreement between the two sides.
"We will provide permits, we will promote salaries, we will promote all kinds of civil projects and in return, you will keep the whole Gaza Strip calm," he said.
Israeli officials declined to comment on day-to-day relations with Hamas authorities in Gaza. Hamas denies it makes any concessions to Israel in return for economic benefits.
Islamic Jihad, which has no governing responsibility in Gaza, has a freer hand and has recently been more aggressive in taking on Israel from Gaza, pointing to possible frictions between the two groups, said Hani al-Masri, a political analyst based in the West Bank city Ramallah.
"The gap between Hamas and Islamic Jihad is rooted in the fact that Hamas has a political programme and governing authority, whereas the Jihad has neither," he said.
However, Israeli officials say Islamic Jihad would not be able to fire rockets without approval from Hamas.
The two Palestinian groups deny they have any major differences and say all decisions during the recent fighting went through their Joint Operations Room, which coordinates activities of Palestinian armed groups in Gaza.
Taher Al-Nono, political adviser of Hamas chief Ismail Haniyeh, said there was "a complete state of harmony and understanding". An Islamic Jihad official offered a similar line.
"Al-Quds Brigades got the lion's share of the response since those who were assassinated were its leaders," said one Palestinian militant official, using the name of Islamic Jihad's armed wing. "That was the tactic."
The next potential test of Hamas restraint could come as early as Thursday when Israeli nationalists hold an annual "Flag Day" march through the Muslim Quarter of the Old City of Jerusalem, celebrating Israel's victory in the 1967 Middle East War.
Hamas has stayed out of previous rounds of fighting in Gaza between Israel and Islamic Jihad over an Islamic Jihad hunger striker who died in Israeli custody earlier this month and over a senior official who was arrested last August.
Instead it has sought to build its status as leader of the Palestinian resistance by focusing on tensions in the West Bank and around Al-Aqsa mosque in Jerusalem, the most sensitive point between Muslims, for whom the mosque is the third most holy place, and Jews who revere the site as Temple Mount, the location of two ancient temples.
Hamas has encouraged shows of defiance such as the uproar surrounding an Israeli police raid on the mosque compound during Ramadan. Dozens of Hamas militants have also been killed over the past year during an escalation of violence that has brought the territory to the brink of a new Intifada, or uprising.
With 87-year-old Palestinian President Mahmoud Abbas likely to be nearing the end of his time in power, the future of the West Bank-based Palestinian Authority is unclear, with a potential vacuum opening up when Abbas departs the scene.
"That's why they (Hamas) focus their attacks in the West Bank," the regional diplomat said. "They hurt Israel and they embarrass the Palestinian Authority before its people and before Israel as well."
(This story has been refiled to fix the dateline)
(Additional reporting by Ali Sawafta in Ramallah, Dan Williams in Jerusalem; Editing by Edmund Blair)