Israeli strikes hit Lebanon and Gaza early on Friday, in response to rocket attacks it blamed on militant group Hamas.
Tensions have flared in the region following police raids on the al Aqsa Mosque in Jerusalem this week.
Blasts rocked different areas of Gaza, as Israel said its planes hit targets including tunnels and weapons manufacturing sites of Hamas, which controls the blockaded southern coastal strip.
The military said it had also struck Hamas targets in southern Lebanon, where residents around the area of the Rashidieh refugee camp reported three loud blasts.
The strikes came in response to rocket attacks from Lebanon towards northern Israeli areas, which Israeli officials blamed on Hamas.
The Israeli military said 34 rockets were launched from Lebanon, of which 25 were intercepted by air defence systems.
It was the biggest such attack since 2006, when Israel fought a war with the Hezbollah movement.
“Israel’s response, tonight and later, will exact a significant price from our enemies,” Prime Minister Benjamin Netanyahu said following a security cabinet meeting.
As the Israeli jets struck in Gaza, rockets were fired in response and sirens sounded in Israeli towns and cities in bordering areas, however there were no reports of serious casualties.
The strikes came amid an escalating confrontation over Israeli police raids at the al Aqsa Mosque compound in Jerusalem during the Muslim holy month of Ramadan, which this year coincides with the Jewish Passover holiday.
In a statement, Hamas said: “We hold the Zionist occupation fully responsible for the grave escalation and the flagrant aggression against the Gaza Strip and for the consequences that will bring onto the region.”
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The Israel Defence Force said: “The IDF struck targets including terrorist infrastructures belonging to Hamas in southern Lebanon.
“The IDF will not allow the Hamas terrorist organisation to operate from within Lebanon and hold the state of Lebanon responsible for every directed fire emanating from its territory.”