The Israeli air force resumed overnight its recent series of airstrikes in the Gaza Strip, as Israeli Prime Minister Benjamin Netanyahu warned of the consequences if Palestinian rocket fire continued.

The first air strikes on the southern Gaza city of Khan Younis killed a militant of the Islamic Jihad and wounded another man, Palestinian sources said.

The Israeli military confirmed the attack, saying it had targeted a member of Islamic Jihad who "was involved in planning a massive terrorist attack in the heart of Israel."

"This operation disrupts the execution of the attack by Islamic Jihad," an Israeli army spokeswoman said.

"That organization has been involved in the firing of rockets towards Israeli territory and IDF forces in the past few days," she added.

Adham Abu Selmiya, spokesman for the Hamas-run health services in the Gaza Strip, named the dead man as 25-year-old Mohammed Jamil An-Najar.

The Al-Quds Brigades, the armed wing of the Islamic Jihad militant group, said An-Najar was a member and pledged revenge for the attack.

Later raids hit three sites used by Hamas security south of Gaza City and also a training base of the Islamic Jihad group in Khan Younis, but caused no further casualties, Hamas officials and eyewitnesses said early Wednesday.

The Hamas facilities housed offices of the Hamas National Security Service and its naval wing, they said.

An Israeli military spokesman confirmed only that aircraft had hit three "terror targets" in response to recent rocket and mortar fire from Gaza.

Tensions have been rising in recent weeks with militants firing dozens of rockets and mortar shells into southern Israel and the Israelis responding with air strikes.

In the most recent incident a rocket fired from Gaza hit open ground in the Negev desert, causing no casualties or damage.

Several rockets, however, have hit populated areas, causing injuries and property damage.

On Tuesday night, Netanyahu warned of the consequences if the rocket fire were to continue.

"I think they'll make a terrible mistake; to test our will, to test our people," he told a gathering of foreign journalists in Jerusalem. "I think they'll make a terrible, terrible mistake."

Israel launched the devastating "Operation Cast Lead" in December 2008 in response to rockets fired from Gaza into its territory.

The 22-day war, which ended in a unilaterally declared Israeli ceasefire on January 18, 2009, killed 1,400 Palestinians, around half of them civilians, and 13 Israelis, 10 of them soldiers.

The Hamas rulers of the Gaza Strip have said that they do not want another war, and have called on militant groups in the coastal enclave to avoid provoking a new confrontation.