Senior Hamas official Saleh al-Arouri, the terrorist organization's deputy leader outside Gaza, was killed on Tuesday in an alleged Israeli drone strike in Beirut.
His death ignited an immediate backlash from Hamas, who called to freeze all negotiations for another ceasefire with Israel in response, and also sparked concerns in Israel that Iran or its proxies such as Hezbollah could start retaliating against the Jewish state.
Shortly after his death, pro-Iranian media warned of Iranian responses, with Hezbollah officials warning that "Hezbollah will respond to the assassination, and this is settled."
But who was Saleh al-Arouri – and why was he considered one of Israel's top targets in its ongoing war to destroy Hamas and its leaders?
Here is everything you should know.
Who was Saleh al-Arouri?
Saleh al-Arouri was one of Hamas's most senior officials, with his official title having been deputy chairman of the Hamas political bureau. In effect, this made him second to Hamas leader Ismail Haniyeh, as opposed to Yahya Sinwar, who was the terrorist group's leader within Gaza itself.
According to the Meir Amit Intelligence and Terrorism Information Center, Arouri was also responsible for all Hamas terrorist attacks in the West Bank.
However, the longtime Hamas member has had many other roles within the terrorist group over the years. This includes being a founding commander of Hamas's military wing, the Izzadin al-Qassam Brigades, and playing numerous roles in Hamas terrorist actions and establishing terrorist cells in the West Bank.
Most recently, Arouri was not only viewed as one of the master planners of Hamas’s October 7 massacre in southern Israel, but was also one of its main liaisons to Lebanon and Iran.
In addition, the allegedly assassinated Hamas official was credited for giving the order to organize a significant terror operation in 2014 that led to the kidnapping and murder of three teenagers – a terror attack which itself eventually led to the Gaza conflict that year.
Since then he had continued to direct significant terror attacks against Israel from the West Bank, despite long being in the Jewish state's crosshairs, and having a $5 million bounty on his head from the US since 2015.
Indeed, throughout his career in Hamas, Arouri has spent a few years behind bars in Israeli prisons, having been arrested
In 2011, Arouri was heavily involved in the Gilad Schalit deal, which saw over 1,000 terrorists, including Sinwar, released in exchange for Hamas freeing captured IDF soldier Gilad Schalit.
Why was Saleh al-Arouri so important?
According to the US Treasury, Arouri was one of Hamas's key financiers and financial facilitators, with the Meir Amit Intelligence Center stating that he had been helping Hamas with weapons transfers and funding since 1987.
In addition to his role as a financier and in planning terrorist attacks, Arouri served another important function for Hamas: He was able to go throughout the Middle East and drum up support for it from local regimes and could help funnel funds to the terrorist organization and its cells in the West Bank.
Over the past 13 years, Arouri lived in Jordan, Syria, Turkey, Qatar, and Lebanon. During this time, he was able to help the group build up its resources, gaining more legitimacy and funds.
Some experts are now predicting that this marks the end of an era for Hamas as a whole.
According to Jerusalem Post analyst Seth Frantzman, al-Arouri "was a living embodiment of Hamas terrorist privilege. His ability to move around the region with ease was an example of how the genocidal terrorist group operated openly... With Iran’s backing and cash support, it was able to manipulate the region and also build up its massive terrorist infrastructure in Gaza. Arouri was a key part of that machine."
It remains to be seen who will take up Arouri's place in Hamas's political bureau.
Tzvi Joffre, Yonah Jeremy Bob, and Seth J. Frantzman contributed to this report.