Hundreds of Beirut residents fled their homes on Sunday night as blasts were heard across its southern suburbs after Israel’s military said it was preparing strikes on branches of a banking system linked to Hezbollah, a further escalation of Israel’s nearly month-long war against the militant group.

Reuters witnesses saw dense plumes of black smoke billowing in the air in Lebanon’s capital after at least 10 blasts. Witnesses, who spoke on the condition of anonymity, said a building located in the Chiyah neighbourhood in the southern suburbs was reduced to rubble and the few people in the area had fled ahead of the explosion, resulting in no casualties.

The Israel Defense Forces (IDF) had warned people to immediately leave areas linked to Al-Qard Al-Hassan Association, a US-sanctioned financial organisation that has more than 30 branches across Lebanon including 15 in densely populated parts of central Beirut and its suburbs.

The National news agency (NNA) in Lebanon reported 11 strikes in southern Beirut, many of them targeting Al-Qard Al-Hassan. Other strikes hit the association in Lebanon’s eastern Bekaa valley and in the country’s south, NNA added.

It also reported that a strike had landed near Beirut’s airport, the main entry-point of humanitarian assistance to the country and a major evacuation hub for those fleeing the conflict. AFP footage showed large plumes of smoke rising close to the facility.

There was no immediate information on what caused the blasts, or details of any casualties. Panicked crowds clogged the streets and caused traffic jams in some parts of Beirut as they tried to get to neighbourhoods thought to be safer, witnesses told Reuters.

The US says Al-Qard al-Hassan is used by Iran-backed Hezbollah to manage its finances. It provides loans and services primarily to people who live in areas where the militia group is popular.

IDF spokesperson Avichay Adraee said on X: “Residents of Lebanon, the IDF will begin attacking infrastructure belonging to the Hezbollah Al-Qard Al-Hassan Association – get away from it immediately.”

He accused the association of involvement in in “financing the terrorist activities of the Hezbollah organization against Israel, and therefore the IDF has decided to attack this terrorist infrastructure”.

Asked by journalists whether the branches could be considered military targets, a senior Israeli intelligence official said: “The purpose of this strike is to target the ability of Hezbollah economic function both during the war but also afterwards to rebuild and to rearm … on the day after.”

The US treasury department said in 2021 while preparing sanctions against Hezbollah’s financial network that Al-Qard Al-Hassan “purports to serve the Lebanese people” but in practice “illicitly moves funds through shell accounts and facilitators”, the New York Times reported.

According to the Times, Al-Qard al-Hasan said in a statement on Sunday that Israel had exhausted “its bank of objectives and has chosen to threaten and target Al-Qard al-Hasan, the non-profit organization.”

Israel has intensified its military campaigns both in Gaza and Lebanon, days after the killing of Hamas leader Yahya Sinwar raised hopes of an opening for ceasefire negotiations to end more than a year of conflict.

Israeli defence minister Yoav Gallant told troops on Sunday that the military was stepping up strikes on Hezbollah in Lebanon, destroying places the group “planned to use as launchpads for attacks against Israel”.

About 70 projectiles were fired from Lebanon into Israel on Sunday within a matter of minutes, the military said, adding it had intercepted some of them.

Separately, the UN peacekeeping force in Lebanon (Unifil) said on Sunday evening that an Israeli army bulldozer had deliberately demolished an observation tower and perimeter fence at its position in Marwahin in southern Lebanon.

Unifil said in a statement: “Yet again, we remind the IDF and all actors of their obligations to ensure the safety and security of UN personnel and property and to respect the inviolability of UN premises at all times.”

Meanwhile, world powers are awaiting Israel’s retaliation against Iranian strikes on the Jewish state on 1 October that were launched in support of Tehran’s Lebanese ally. Late on Friday, it emerged that top-secret US documents that allegedly reveal details about Israel’s plans to attack Iran had been leaked and published online.

With Agence France-Presse and Reuters