Military officials said several people were injured on Saturday when at least three rockets hit the ancient town on the western shore of the Sea of Galilee.
"The Islamic Resistance fires dozens of rockets for the first time on Tiberias," said an announcement on Hezbollah's television station Al-Manar.
The Israeli military said another dozen rockets were fired into northern Israel at dawn on Saturday.
Rockets struck several towns, including the coastal resort of Nahariya, but caused no casualties or damage, a military source told AFP.
Two Israeli civilians, an elderly woman and her five-year-old grandson, were killed on Friday in the deadliest rocket attack in three days, taking the Israeli civilian death toll to four.
More than 40 people were taken to hospital on Friday, three in a serious condition, as about 90 rockets hit about 15 northern Israeli towns.
Syria's ruling Baath Party has said it would support Hezbollah and Lebanon against the "barbaric Israeli aggression".
The pledge came despite the sometimes hostile relations between Damascus and Beirut since Syria ended its 29-year military presence in Lebanon last year.
The Beirut government, led by an anti-Syrian coalition, is unable or unwilling to disarm Hezbollah, the only Lebanese faction to keep its guns after the 1975-90 civil war.