The Lebanese militant group Hezbollah has launched an attack on Israel with a large number of drones in retaliation for the killing of one of its commanders in Beirut.

Hezbollah said the attack was targeting "a qualitative Israeli military target that will be announced later" as well as "targeting a number of enemy sites and barracks and Iron Dome platforms."

It said the strikes were an initial response to the killing of Fouad Shukur, a top commander with the group, in a strike in Beirut's southern suburbs last month.

Earlier, Israel launched a series of air strikes in Lebanon in what its military said was a pre-emptive strike against the Hezbollah militant group. 

In a statement, the Israeli military accused Hezbollah of "preparing to fire missiles and rockets toward Israeli territory" on Sunday morning, local time. 

"‎‏In a self-defence act to remove these threats, the (Israeli military) is striking terror targets in Lebanon, from which Hezbollah was planning to launch their attacks on Israeli civilians," Israeli military spokesman Rear Admiral Daniel Hagari said.

Mr Hagari warned Hezbollah would "soon fire rockets, and possibly missiles" and drones into Israel. 

Sirens sounded in northern Israel soon after the warning.

Israel’s Ben Gurion International Airport outside Tel Aviv began diverting incoming flights and delaying others due to take off.

Israeli media cited the Israel Airports Authority for the news.

Flight-tracking data showed at least two El Al flights swinging far south and diverting after the announcement.

Lebanese media reported strikes in the country's south without immediately providing more details. 

Social media footage showed what appeared to be strikes in southern Lebanon.

"We can see that Hezbollah is preparing to launch an extensive attack on Israel, while endangering the Lebanese civilians," Mr Hagari said in his statement.

Mr Hagari didn't provide additional details on the intelligence he cited.

"‎‏We warn the civilians located in the areas where Hezbollah is operating to move out of harm's way immediately for their own safety," he said.

Fears have been high in recent weeks that the Israel-Hamas war in the Gaza Strip could escalate into a regional conflict after an Israeli strike killed a senior Hezbollah commander and a suspected Israeli assassination operation in Iran killed Hamas leader Ismail Haniyeh.