Lebanon’s state-run National News Agency said the blast killed four people and was carried out by an Israeli drone.

An explosion shook the Lebanese capital’s southern suburbs Tuesday evening causing chaos in the militant Hezbollah group’s stronghold, but the nature of the blast was not immediately known.

It wasn’t clear if the explosion inflicted any casualties in the Beirut suburb but videos circulating on social media showed serious damage and fire.

The explosion came during more than two months of heavy exchanges of fire between Israeli troops and members of Hezbollah along Lebanon’s southern border.

Since the fighting began on Oct. 8, the fighting has been concentrated a few miles (kilometers) from the border but on several occasions Israel’s air force hit Hezbollah targets deeper in Lebanon.

Earlier in the day, Hezbollah said its fighters carried out several attacks along the Lebanon-Israel border targeting Israeli military posts.