Israel launched air strikes against Hamas in the Gaza Strip late Thursday after vowing retaliation for a barrage of cross-border rockets fired from Lebanon, which it blamed on Palestinian groups.
Tensions have soared between Israel and Palestinians during what is both the Jewish Passover and the Muslim holy month of Ramadan, prompting condemnations and calls for restraint from abroad.
The latest flare-up of violence comes after Israeli police clashed Wednesday with Palestinians inside Jerusalem's Al Aqsa Mosque – Islam's third-holiest site.
On Thursday, Israel's army said 34 rockets had been fired from Lebanese territory into Israel in the largest escalation along the frontier since Israel and Hezbollah fought a 34-day war in 2006.
Prime Minister Benjamin Netanyahu vowed that Israel's enemies would "pay the price for any act of aggression".
Shortly thereafter, AFP journalists heard explosions ringing out in the Gaza Strip.
The Israeli army said in a statement it had hit two tunnels and "two weapon manufacturing sites" belonging to Hamas "as a response to the security violations of Hamas during the last few days."
The raid was followed by several missiles fired from Gaza towards Israel.
In a statement, Hamas said Israel was "responsible for this aggression and its consequences" and called for all Palestinian groups to unite against "the occupation".
The Israeli army said its air defence systems intercepted 25 of the rockets fired and five landed in Israeli territory.
Army spokesman Lt Colonel Richard Hecht blamed Palestinian groups for the attack.
"We know for sure it's Palestinian fire," he told reporters. "It could be Hamas, it could be Islamic Jihad, we are still trying to finalise, but it wasn't Hezbollah.
"We assume Hezbollah knew about it, and Lebanon also has some responsibility. We are also investigating whether Iran was involved," he added.
Lebanon rejects 'escalation'
Lebanon's caretaker prime minister Najib Mikati said he rejected any "escalation" from his country after the rocket attack.
Israeli emergency services reported one man lightly wounded by shrapnel and a woman injured while running to a shelter during the attack.
Inspecting his damaged office in the town of Shlomi, 46-year-old Shlomi Naaman told AFP: "I heard the siren, I heard the boom, I was in my home, it was very, very scary."
The United Nations Interim Force in Lebanon, which patrols the border area between the two countries that are technically still at war, urged restraint.
"The current situation is extremely serious," said the force. "Unifil urges restraint and to avoid further escalation."
"Given the volatile and dangerous situation, per standard protocol, civilian and military staff were ordered to seek shelter in bunkers on their bases," the UN force added.
The Israeli army earlier denied reports from Lebanon's National News Agency that it had struck targets in southern Lebanon.
According to the Lebanon report, Israeli artillery fired "several shells from its positions on the border" towards the outskirts of two villages after the launch of "several Katyusha type rockets" at Israel.
Defence Minister Yoav Gallant "completed a situation assessment with senior officials in Israel's defence establishment", after which he instructed "to prepare all the possible responses to recent events," a statement said.
Al Aqsa clashes
Israeli riot police had on Wednesday stormed the prayer hall of Al Aqsa Mosque in a pre-dawn raid aiming to dislodge "law-breaking youths and masked agitators" they said had barricaded themselves inside.
The violence, during both the Jewish Passover and the Muslim holy month of Ramadan, sparked an exchange of rockets and air strikes with militants in the Gaza Strip.
The US said it recognised "Israel's legitimate right to defend itself against all forms of aggression", State Department spokesman Vedant Patel told reporters.
UN chief Antonio Guterres condemned the rocket fire from Lebanon, calling on "all actors to exercise maximum restraint".
France condemned what it called "indiscriminate rocket fire targeting Israeli territory from Gaza and southern Lebanon".
Lebanon's Iran-backed armed movement Hezbollah had warned earlier Thursday it would support "all measures" that Palestinian groups may take against Israel after the clashes.
The Lebanese group has close ties with the Islamist movement Hamas, which rules Gaza, and with the Islamic Jihad militant group, which is also based in the coastal enclave.
The rockets came a day after Hamas leader Ismail Haniyeh arrived in Lebanon for a visit.
Haniyeh late Thursday said the Palestinians would not "sit with their arms crossed" in the face of Israeli "aggression" against Al Aqsa.
He called in a statement on "all Palestinian organisations to unify their ranks and intensify their resistance against the Zionist occupation (Israel)".
The last rocket fired from Lebanon into Israel was in April 2022.