The latest raids struck three sites used by Hamas security south of Gaza City and also a training base of the Islamic Jihad group in the southern city of Khan Yunis, said the sources.
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 a total of three "terror targets" in response to recent rocket and mortar fire from Gaza.
The strikes came hours after Israeli aircraft killed a member of the Islamic Jihad and wounded another man, also in Khan Yunis.
Dozens of rockets and mortar shells have been fired into southern Israel in the recent weeks, and the Israelis have responded with air strikes, say officials.
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, Israeli Prime Minister Benjamin 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 hundreds of rockets fired from Gaza into its territory.
The 22-day war, which ended in a ceasefire on January 18, 2009, killed 1,400 Palestinians, around half of them civilians, and 13 Israelis, 10 of them soldiers.
COMMENTS
Comments are moderated and generally will be posted if they are on-topic and not abusive.
For more information, please see our Comments FAQ