Story highlights Israeli plane fires on two targets, Israel Defense Forces says

Strikes hit empty land; no injuries reported

Previously unknown group claims to have fired rocket into Israel

Israel conducted two airstrikes inside Gaza on Tuesday night, security sources in Gaza told CNN.

The sources told CNN this was the first Israeli airstrike there since a truce that ended eight days of fighting between the Israelis and Hamas last November.

Medical sources said there were no initial reports of casualties.

The strikes hit empty land north and west of the city of Gaza, security sources said.

Israel Defense Forces issued a statement acknowledging Israeli Air Force strikes.

"In response to several rocket fire incidents directed at Israel, an IAF aircraft targeted overnight two extensive terror sites in the Northern Gaza Strip. Accurate hits were identified," it said.

"The IDF holds the Hamas terror organization solely responsible for all activity in the Gaza strip and all terror activity against Israel."

It said the IDF will not allow rocket attacks to escalate as they did before the November conflict.

However, the security sources in Gaza told CNN a leaflet distributed by an unknown militant group called Khalid Ibn Al-waleed claimed responsibility for firing a rocket into Israel from Gaza on Tuesday. They said another rocket was launched after the airstrikes.

The sources say there is no known connection between Khalid Ibn Al-waleed and Hamas.