An Israeli drone strike killed a top Hamas politburo member in a major suburb south of Beirut on Tuesday, according to reports from Reuters and Lebanese media at the scene, where a fire continued to burn in the hours after the attack.

Israeli officials did not confirm responsibility for the attack, but one top adviser to Prime Minister Benjamin Netanyahu told Reuters that “whoever did this did a surgical strike against the Hamas leadership,” not against Lebanon itself. (By contrast, prominent Israeli lawmaker Danny Danon congratulated the Israel Defense Forces for the strike and encouraged future strikes outside of Gaza.)

The adviser’s comment likely aims to limit the chance that Hezbollah, which is a strong supporter of Hamas, will feel obligated to respond to the attack. Hezbollah leader Hasan Nasrallah is scheduled to deliver a speech Wednesday, which observers will watch closely for any indications that the militant group intends to expand attacks on Israel.

Hezbollah will “definitely” respond to the strike as an escalation but will likely try to avoid sparking a full-scale war with Israel, argued Trita Parsi of the Quincy Institute, which publishes RS.

“Instead, Hezbollah will likely strike deeper into Israel but without revealing its new capabilities,” Parsi wrote on X, formerly known as Twitter. However, such a move “may very well spark a full war, particularly if very successful,” he added.

Saleh al-Arouri, the Hamas leader who was killed, helped found the Qassam Brigades, the movement’s militant arm. He was serving as the deputy chairman of Hamas’ politburo and the leader of the group’s military operations in the West Bank at the time of his assassination. Israel destroyed Arouri’s house in the West Bank in October, but he is believed to have lived in Lebanon since 2018.

Five others died in Monday’s attack. Their identities remain unknown, though some local media have reported that two additional members of Hamas died in the strike.

The drone attack is a rare example of Israel striking Beirut directly. Lebanese Prime Minister Najib Mikati described the move as “a new Israeli crime aimed at dragging Lebanon into a new phase of confrontations after the continuous daily attacks in the south.”

Hamas, for its part, said the move would not affect operations against Israel and argued that it represented “evidence of the enemy's failure to achieve its objectives in Gaza.”

The attack is the latest escalation in a months-long shadow war between the U.S. and Israel on one side and Iran and its regional allies on the other.

In Syria and Iraq, American forces have been attacked by militias sympathetic to Iran over 100 times since October, leading to some injuries but no deaths. The U.S. has responded with a handful of strikes. An Israeli airstrike killed more than 20 people, including several Hezbollah members, in eastern Syria over the weekend.

Meanwhile, the Houthis in Yemen have dramatically cut back Red Sea shipping — and thus transits of the Suez Canal — by attacking merchant ships that they claim are tied to Israel. The U.S. has formed an international task force to stop the attacks and sank at least three Houthi boats on Saturday as they attempted to board a cargo ship.

The latest strike is a reminder that “as time has passed and Biden has refused to push for a ceasefire, we are getting closer and closer to a full war in the region,” argued Parsi.

“The most effective way of de-escalating is by securing a ceasefire in Gaza,” he continued, noting that an end to hostilities there would likely stop Houthi attacks as well as strikes on U.S. bases in Iraq and Syria. “Biden is not only facilitating the slaughter and ethnic cleansing in Gaza, but he is increasingly also failing to keep Americans safe and America out of war.”