Israel has launched three separate air strikes in the Gaza Strip, killing six Palestinians, including a senior member of the Islamic Jihad militant group.

Three militants were killed in the first attack, which struck a vehicle in Khan Yunis. Four civilians were also hurt, rescue workers said.

A spokesman for Islamic Jihad, Abu Ahmed, said one of the dead men was the group's leader in southern Gaza.

Hours later, three Palestinians were killed in a second Israeli strike.

That air strike hit a metal workshop in the Maghazi refugee camp in central Gaza.

The owner was among the dead and two other people were wounded, medics said.

The third strike targeted the same workshop, Palestinian witnesses said, and at least four people were injured.

Speaking after the first air strike, Israel said it had targeted militants who had planned terror attacks.

The strike came after a rocket was fired at Israel from Gaza but landed inside Palestinian territory, Reuters news agency reported.

The dead Islamic Jihad leader was Raed Ghannam, said to be wanted by Israel for rocket and other attacks, the agency said.

'This will not affect Islamic Jihad. We continue our path of resistance until martyrdom or victory,' Ahmed said.

On Wednesday, at least 12 Palestinians were killed in Israeli raids on Gaza City and Khan Yunis.

Earlier this month Hamas took control of the Gaza Strip, following deadly clashes with its rival Fatah faction.

The situation led Palestinian Authority President Mahmoud Abbas, also the Fatah leader, to dissolve the national unity government and declare a state of emergency.

Hamas is now in control of Gaza, while Fatah retains control of the West Bank.