The strikes, targeting senior militant commanders Israel said had planned attacks from Gaza and the Israeli-occupied West Bank, were the latest in an extended period of Israeli-Palestinian violence stretching back more than a year.

Islamic Jihad confirmed the death of the commanders, Jihad Ghannam and Tareq Izzeldeen - who an Israeli military spokesman said orchestrated operations in the West Bank and sought to bring rockets to the city of Jenin - as well as Khalil Al-Bahtini who coordinated rockets fired at Israel a week earlier.

As explosions rocked parts of Gaza, a coastal enclave where 2.3 million people live squeezed into an area of just 365 square kilometres, Israeli jets also hit rocket production workshops and military compounds, sending columns of smoke into the sky.

Dawoud Shehab, a spokesperson for the Iranian-backed Islamic Jihad, said Israel "must expect a response at any moment and anywhere".

Israeli Prime Minister Benjamin Netanyahu said he had instructed the security forces to prepare for any scenario, including an escalation on more than one front.

"In the coming days we will all be required to show patience and resolve," Netanyahu told a press conference in Tel Aviv.

In all, at least 15 Palestinians were killed in the strikes, including a well-known dentist, his wife and 21-year-old son who lived in the same Gaza City apartment block as militant leader Izzeldeen, as well as seven other civilians including women and children elsewhere in the enclave, Palestinian officials said.

Two men died later, Palestinian paramedics said, after Israeli jets hit what the military called an anti-tank team near the southern border of Israeli-blockaded Gaza.

Israeli military spokesmen said the "pinpoint" operation involved 40 aircraft but they confirmed that women and children had been killed.

While the West Bank and Jerusalem have seen a spread of Israeli-Palestinian violence over the past year, exchanges of fire across the fortified Gaza border have also intensified - most recently following the death last week of an Islamic Jihad leader on hunger strike in Israeli custody.

Israel on Tuesday closed roads in towns near the Gaza border, told residents there to keep close to bomb shelters and said it was calling up some military reservists.

Images on social media showed Iron Dome rocket interceptor batteries being taken by truck to the area.

'MORE RESISTANCE'

Islamic Jihad, based in Gaza alongside the larger and more powerful Hamas movement which runs the territory, is one of an array of militant groups that have been increasingly clashing with Israel over the past year.

Israeli officials said that much would depend on how closely Hamas chose to identify itself with any response to the air strikes.

"Assassination of leaders will not bring the Occupation (Israel) security but more resistance," Hamas chief Ismail Haniyeh, who has divided his time recently between Qatar and Turkey, said in a statement.

The Palestinian foreign ministry, based in Ramallah in the West Bank, condemned Israel's air strikes and said a negotiated solution was the only way to achieve security.

Egypt, which has brokered past ceasefires in Gaza, said the Israeli strikes "contradicted the foundations of international law and international resolutions". Qatar condemned the strikes while special U.N. Middle East peace coordinator Tor Wennesland condemned the killing of civilians and called for restraint.

The developments offered a political reprieve for Netanyahu.

Jewish Power, a far-right party in his coalition government, said it was ending a boycott of parliamentary voting called in protest at what it deemed lax policy on Gaza, attributing its decision to "the transition from containment to attack".

More than 100 Palestinians and at least 19 Israelis and foreigners have been killed in violence since January.

Israel captured Gaza and the West Bank, areas Palestinians want for an independent state with East Jerusalem as its capital, in a 1967 war. Israeli forces and settlers withdrew from Gaza in 2005. Peace talks have been frozen since 2014.