Hezbollah said on Sunday its fighters had bombarded two army bases in the Israeli-annexed Golan Heights within hours after deadly Israeli strikes on south Lebanon.
Hezbollah, a Hamas ally, has traded regular cross-border fire with Israel since 7 October.
The border clashes have intensified, and on Sunday, Hezbollah "bombarded... the headquarters of the 210th Golan Division in the Nafah barracks with dozens of Katyusha rockets", the powerful Iran-backed group said in a statement.
It said the attack was in retaliation for Israeli strikes in eastern Lebanon's Bekaa Valley. A source close to Hezbollah said two fighters were wounded.
The Israeli military said "approximately 15 projectiles" had been fired from Lebanon at the Golan Heights and "fell in open areas", causing no injuries but starting fires.
The Hezbollah announcement came several hours after Israeli forces struck the group's positions in eastern and southern Lebanon.
The state-run National News agency reported that "two civilians were killed in an Israeli strike that targeted their home in the village of Hula," near Lebanon's southern border with Israel.
Israeli jets had "struck a Hezbollah military structure in the area of Hula, from which projectiles were fired" at an Israeli village across the border, the military said.
A local official told AFP that the fatalities were "two brothers, shepherds whose house was destroyed."
Earlier on Sunday, Hezbollah said it had launched several attack drones towards an army base in the Golan Heights, hours after Israel targeted the group's fighters in a remote area of Bekaa Valley, far from the border.
The Israeli military said Sunday that in response to Hezbollah firing a missile at one of its drones "operating in Lebanese airspace" the day before, its "fighter jets struck a military compound used by the Hezbollah terrorist organisation in the area of Bekaa in Lebanon".
Since Friday, Israel has been intensely shelling a series of villages in southern Lebanon, where a woman, a Hezbollah-affiliated rescuer and two fighters from the group were killed.
In response, Hezbollah said it launched several attacks on Israeli military targets and shot down an Israeli Hermes 900 drone.
Nearly eight months of violence on the Israel-Lebanon border has left at least 451 people dead in Lebanon, mostly fighters but including more than 80 civilians, according to an AFP tally.
On the Israeli side, at least 14 soldiers and 11 civilians have been killed, according to the army.