Child, Palestinian commander among 15 dead as Israel strikes Gaza

Before the latest strikes, at least 55 Palestinians have been killed since late March

A five-year-old girl child and a senior member of the Islamic Jihad group were among more than 15 people killed in Israeli air strikes on the Gaza Strip on Friday, prompting the fighter group to warn Israel has "started a war".

Later in the day, Israeli authorities issued warnings of rocket strikes against Israeli cities, and said sirens had been sounded in central and southern areas following a series of airstrikes against Gaza.

The enclave's Health Ministry confirmed the child was among those killed while Israel's military estimated 15 combatants were killed. 

Prior to the latest strikes, at least 55 Palestinians have been killed since late March, mostly in the West Bank.

Over the same period, 19 others have been killed, mainly in attacks by Palestinians. 

The Israeli army said the strikes were part of an operation "against targets in the Palestinian Islamic Jihad" group.

In its reaction, the group announced that it would target Tel Aviv.

"The Zionist enemy started this aggression and it must expect us to fight non-stop... There will be no truce after this bombing," its leader Ziad al-Nakhala told Lebanon's Al-Mayadeen television channel from Tehran, where he has been visiting in recent days.

"There are no red lines in this battle... Tel Aviv will also be one of the targets of the resistance's missiles... as will all Zionist cities," he said.

The Islamic Jihad secretary-general called on his fighters and on militants from all Palestinian factions to fight "as one" to face Israeli "aggression".

Vowing self-defence, Islamic Jihad said Israel had "started a war against our people" as it was mourning "the great jihadist commander Tayseer al-Jabari 'Abu Mahmud', who was killed in a Zionist assassination in Gaza City".

An Israeli military spokesman said: "We haven't finished yet".

The strikes come four days after Israel closed its two border crossings with Gaza and restricted the movement of Israeli civilians living near the frontier, citing security concerns.

The measures follow the arrest in the occupied West Bank of two senior members of Islamic Jihad, which has a strong presence in Gaza.

Hamas, the Gaza rulers, said Israel has "committed a new crime for which it must pay the price".

"The resistance in all its military arms and factions is united in this struggle and will speak loudly, as we cannot accept the situation as it is... all fronts must open fire on the enemy," Hamas.

Israeli Prime Minister Yair Lapid was due to hold talks with Defence Minister Benny Gantz on Friday evening.

"The Israeli government will not allow terrorist organisations to set the agenda in the Gaza Strip and threaten the citizens of the State of Israel. The security forces will act against the Islamic Jihad terrorists to remove the threat," Lapid said.

Gantz visited communities near Gaza earlier on Friday, saying authorities were preparing “actions that will remove the threat from this region,” without elaborating.

Earlier in the day, a couple of hundred Israelis protested near the Gaza Strip to demand the return of a captive and the remains of two Israeli soldiers held by Hamas.

Islamic Jihad is blacklisted as a terrorist organisation by the European Union and the United States.

In the afternoon, the Israeli military banned large gatherings in communities within 80 kilometres of the Gaza frontier, until this evening.