The low-flying planes rattled windows throughout Beirut on Tuesday, a reminder of the Israeli military’s capacity for devastation in Lebanon as Hezbollah leader Seyyed Hassan Nasrallah promised retaliation for a series of Israeli assassinations.

“The Israelis chose escalation by carrying out assassinations,” Nasrallah said, adding that the group’s response would be “strong and effective” and carried out either alone or in coordination with other members of the Iran-backed “axis of resistance”.

“We will respond, but with deliberation and prudence,” the Hezbollah chief continued, stating, “Israel’s waiting for our response is part of the punishment.”

Tensions between Israel and the powerful group are at their highest levels since the two sides began a series of limited, back-and-forth exchanges in October, with thousands displaced on both sides of the border.

The Israeli assassination of Hezbollah commander Fuad Shukr in Beirut last week, followed by a similar strike that killed Hamas political leader Ismail Haniyeh in Tehran, has all but guaranteed retaliatory attacks that experts worry could set off a full-scale war.

Hezbollah announced on Tuesday that it had sent a swarm of drones to attack Israeli military positions in northern Israel, and Israeli authorities reported that 12 people south of the city of Nahariya were taken to the hospital after an Israeli missile interceptor misfired and struck the ground.

Seven others were injured in a drone attack, according to the Nahariya Medical Center. The Associated Press reported that six Israeli soldiers were among the injured.

Lebanon’s Ministry of Public Health said that an Israeli raid on the southern town of Mayfadun killed five people, with an Israeli attack near Adaysseh killing another.