Israeli officials say airstrikes on Gaza have targeted the Palestinian Islamic Jihad (PIJ) movement rather than Hamas, the militant group which rules the enclave. What is the difference between the two groups?
The PIJ is a militant group allied with Hamas, both with a background in the Muslim Brotherhood, a shared hostility to Israel and an ideological commitment to the creation of an Islamic Palestinian state.
But the two groups have separate identities and some differences.
Whereas Hamas leaders have made statements softening their commitment to the destruction of Israel, the smaller PIJ has made no such move and rejects any compromises with Israel.
On Friday, as he explained the airstrikes on Israeli television, Prime Minister Yair Lapid described the group as "an Iranian proxy that wants to destroy the state of Israel".
While it does not have as many long-range rockets as Hamas, PIJ does have a significant arsenal of small arms, mortars, rockets and anti-tank missiles and an active armed wing called the Al Quds, or Jerusalem Brigades, that has attacked many Israeli targets over the years.
Friday's airstrikes killed Tayseer al-Jaabari, a senior commander who Israel said was the commander of the movement's northern region, responsible for planning attacks against Israeli citizens and military targets.
Up-to-date figures on PIJ's strength are difficult to come by, with estimates from last year ranging from about 1,000 to several thousand, according to the CIA's World Factbook.
Both Hamas, which has fought five conflicts with Israel since 2009, and PIJ are listed as terrorist organisations by the West. Both get funds and weapons from Iran, where PIJ leader Ziyad al-Nakhalah was reported to have been meeting Iranian President Ebrahim Raisi on the day of the strikes.
Unlike Hamas, PIJ refuses to join elections and appears to have no ambition to form a government in Gaza or the West Bank.
It maintains a significant presence in the West Bank town of Jenin, where Bassam al-Saadi, a senior leader of the movement was arrested last week, setting off the crisis that led to Friday's strikes.
However, its focus on militant activity means it does not have anything like the same infrastructure or responsibilities as Hamas, which has ruled Gaza since 2007, in charge of the government and day-to-day needs of more than 2.3 million people.
Little more than a year since the 11-day war of May 2021, which inflicted huge damage on Gaza's economy, Israel's explicit focus on PIJ targets appears intended to convince Hamas to stay out of the fighting itself.
Zvika Haimovich, a former commander of the Israel Air Defence Forces who served in previous operations against Gaza in 2012 and 2014, said there were significant disagreements with PIJ that could make Hamas stay out.
"The direct immediate interest of Hamas is not to join this operation," he said.
"If Hamas joins this operation it will change totally the situation that we are talking about."