Jordan, one of just two Arab countries to have signed a peace treaty with Israel, demanded Wednesday an immediate halt to deadly Israeli air raids against the Gaza Strip.

Government spokesman Mohammad Momani said that the raids that killed more than 20 Palestinians in purported response to rocket fire that has killed no one in Israel were "barbaric".

The European Union condemned "indiscriminate" rocket fire from the Gaza Strip into Israel on Tuesday and called for an immediate ceasefire as the Jewish state and Hamas squared off in their most serious conflict since 2012.

"The EU strongly condemns the indiscriminate fire into Israel by militant groups in the Gaza Strip," said a statement from the office of the bloc's foreign policy chief Catherine Ashton.

Israeli warplanes killed 15 Palestinians and wounded at least 100 Tuesday, pounding the Gaza Strip in a new campaign to stamp out Hamas rocket fire as the two sides slid toward another major conflict. 

In the most serious flare-up over Gaza since November 2012, it comes as Israel struggles to contain a wave of violence in Arab towns over the grisly murder of a Palestinian teenager by Jewish extremists. 

Turkey called on Israel on Tuesday to "immediately" halt its assault against the Gaza Strip, following the deadly air campaign against the Palestinian enclave.

"We are calling on Israel to immediately halt its attacks on Gaza," the foreign ministry said in a statement.

The Arab League called Tuesday for the U.N. Security Council to hold an urgent meeting to discuss the deadly Israeli air campaign against Gaza, Secretary General Nabil al-Arabi said.

Fourteen people were killed Tuesday and dozens wounded in a number of attacks in the most serious flare-up in and around the Palestinian territory since November 2012.

Three Jewish extremists arrested for the killing of a Palestinian teenager have confessed to the attack, an Israeli official said Monday, as shock waves from the brutal murder continued to spread.

As police struggled to contain five days of violent clashes in annexed east Jerusalem and in Arab towns across Israel, tensions were further raised by a series of Israeli air strikes on Gaza, which killed several Palestinian militants.

The involvement of Jewish extremists in the brutal murder of a Palestinian teenager has forced Israel to confront the growing danger of violently anti-Arab narrative peddled by the far-right fringe. 

"The diabolical murder of 16-year-old Palestinian Mohammed Abu Khder is the Shin Bet's nightmare scenario," wrote Yossi Melman in Maariv newspaper, referring to Israel's internal security agency.

Israeli Foreign Minister Avigdor Lieberman on Monday ended a 20-month political alliance between his party and the ruling rightwing Likud, although his faction will remain in government.

The decision was announced at a press conference after a bitter dispute between Lieberman and Prime Minister Benjamin Netanyahu over the government's handling of intensifying rocket fire by militants in the Gaza Strip. 

Israeli Prime Minister Benjamin Netanyahu on Monday telephoned the father of an east Jerusalem teenager who was kidnapped and killed last week in a suspected revenge attack by Jewish extremists. 

The brutal murder of Mohammed Abu Khder, 16, on Wednesday has sparked days of clashes between angry protesters and riot police which began in annexed east Jerusalem and have since spread to Arab towns in Israel.

Israeli air strikes killed seven militants in Gaza overnight as clashes over the kidnap and murder of a Palestinian teenager raged into the early hours of Monday.

It was the worst bloodshed in Gaza since the start of the current round of violence in and around the territory, which began on June 12 in response to a vast West Bank arrest campaign to find those behind the kidnap and murder of three Israeli teenagers.