Israel blamed Palestinian groups on Thursday for a barrage of rockets fired from Lebanon, an army spokesperson said.

"We know for sure it's Palestinian fire," Lt Colonel Richard Hecht told reporters.

"It's hard to say, it could be Hamas it could be Islamic Jihad, we are still trying to finalise but it wasn't Hezbollah," he continued.

"We assume Hezbollah knew about it, and Lebanon also has some responsibility. We are also investigating whether Iran was involved."

Shiite militant group Hezbollah is the only Lebanese faction that kept its weapons after the end of the country's 1975-1990 civil war.

The salvo of 34 rockets fired on the Jewish holiday of Passover was the largest escalation along the frontier since Israel and Hezbollah fought a 34-day war in 2006.

It came just days after Israeli police drew widespread condemnation and warnings of retaliation from around the region for clashing with Palestinians inside Jerusalem's Al-Aqsa mosque – Islam's third-holiest site. (AFP)