Saleh al-Arouri, the senior Hamas official killed in a suspected Israeli strike in the suburbs of Beirut, played a crucial role in building up the Palestinian group's military capabilities and maintaining its links with regional allies.
Arouri, 57, was one of the founders of Hamas's armed wing, the Izz el-Deen al-Qassam Brigades, in the early 1990s.
More recently, he served as the "channel or link" between the Hamas movement, Iran and Hezbollah, a Hamas source told AFP. He had regularly visited Iran.
On October 25, the Hezbollah-owned Al-Manar TV channel reported that Arouri held a meeting with Hezbollah leader Hassan Nasrallah and the head of the Palestinian Islamic Jihad, Ziyad al-Nakhalah.
Arouri was also considered the leader of Hamas in the West Bank, and the source told AFP that his knowledge and expertise had helped develop the Islamist movement's military capabilities in recent years.
Read moreWho’s who: Top Hamas leaders on Israel’s radar
Considered Hamas's number two at the time of his killing, Arouri had been accused by Israel of playing a role in numerous attacks.
These included Hamas's October 7 attack on Israel, which resulted in the deaths of 1,139 people, according to Israeli government figures. Of that number, 695 were civilians, including 36 children.
After the attack, the worst in its history, Israel began a relentless bombardment and ground offensive that has killed at least 22,313 people in the besieged Gaza Strip, mostly women and children, according to the enclave's health ministry.
Living in exile
Born in the village of Arura, near Ramallah in the occupied West Bank, Arouri studied sharia, the Islamic law based on the teachings of the Koran, at Hebron University.
Arouri became a member of Hamas at the group's founding in 1987, having joined its parent movement, the Muslim Brotherhood, as a young man. He was active in Islamic student politics.
Arouri was detained several times in the early 1990s, and in 1992 was sentenced to 15 years in jail on charges of forming the first cells of the Izz el-Deen al-Qassam Brigades in the West Bank.
He was released in 2007, but detained again three months later until 2010, when he was freed on condition that he go into exile.
Arouri was then deported to Syria, where he remained for three years before relocating to Lebanon.
Following his release in 2010, Arouri was appointed as a member of Hamas's political arm and was on the negotiating team that secured a prisoner exchange involving French-Israeli soldier Gilad Shalit in 2011, along with Egyptian mediators.
On October 9, 2017, Hamas announced the election of Arouri as deputy head of its political arm.
Arouri had been on the US list of terrorists since 2015, with the US State Department offering up to $5 million for information leading to his identification or location.
Arouri was married with two daughters and lived in Beirut.
Who else is left?
With Arouri , Israeli forces will be focusing their attention on other senior Hamas figures.
They include Ismail Haniyeh, the current head of the Hamas political bureau.
Re-elected leader of Hamas in 2021, Haniyeh has been on the US list of Specially Designated Global Terrorists (SDGTs) since 2018, having been accused of having “close links with Hamas’s military wing” and for being “a proponent of armed struggle, including against civilians”.
Considered a pragmatist, Haniyeh lives in voluntary exile, splitting his time between Turkey and Qatar.
He has long campaigned for a reconciliation between the armed resistance against Israel and a political stance within Hamas, which is blacklisted as a terrorist group by the European Union and the United States.
Another target is Yahya Sinwar, the head of Hamas in Gaza.
He rose through the ranks of Hamas as a fierce advocate of armed struggle against Israel and is considered by the group as their "defence minister".
The Hebrew-speaking Sinwar spent 23 years in Israeli jails before his release in 2011 in the Gilad Shalit prisoner exchange.
Mohammed Deif, the head of Hamas's armed wing, has been on the US list of "international terrorists" since 2015. Israel has tried to assassinate him at least six times.
Deif was born in the Khan Younis refugee camp in Gaza in 1960 and trained alongside Yahya Ayyash, a Hamas military leader who was later assassinated by Israel’s internal security service. His wife and two children were killed in 2014 when the Israeli military bombed their house northwest of Gaza City.
Considered by Hamas as the group's "chief of staff", Deif is the one who announced in an audio message the start of the Hamas attack on Israel dubbed "Al-Aqsa Flood".
His hiding place is unknown, and he is reported to be a master of disguise who is able to blend seamlessly into the population. His alias “el-Deif” – "the Guest" – refers to his habit of frequently changing hideouts.
(FRANCE 24 with AFP)