Dozens of rockets fired from Lebanon into Israel.
Major escalation amid tensions over al-Aqsa mosque in Jerusalem.
Largest attack since 2006 war that left 1,200 Lebanese and 165 Israelis dead.
Israel closed northern airspace in response.
No reported deaths yet, group responsible unknown.
Videos show rockets in northern Israel, explosions heard.
Lebanese army and Hezbollah have no public comments.
Incident follows Hamas leader's arrival in Beirut for meetings with Hezbollah.
Israeli PM Netanyahu and Defense Minister Gallant briefed on security situation.
Tensions high after Israeli police storm al-Aqsa mosque in Jerusalem during Ramadan prayers.