Israeli warplanes launched two air strikes on the Gaza Strip early Friday, the military said, hours after Palestinian militants fired two rockets at southern Israel.

"Israeli army aircraft thwarted an attempt by a terrorist squad to fire rockets at Israel from the northern Gaza Strip," an army statement said.

Palestinian sources said two residents of the Zeitun neighbourhood were lightly wounded.

Hours later, the army said it carried out another strike on northern Gaza.

On Thursday night, Palestinian militants fired two rockets at Israel, neither of which caused casualties or damage.

Palestinian militant group the Popular Resistance Committee (PRC) said it had launched a Grad rocket at Israel.

A brief statement said it was "in defence of Al-Quds," the Arabic name for Jerusalem, as recent days have seen a rise in tensions in the Old City compound that houses the Al-Aqsa mosque.

A demonstration in support of Palestinian sovereignty in Jerusalem was to be held in Gaza later on Friday.

The PRC statement comes as the other Palestinian factions were in Cairo, where talks on forming a unity government between Fatah and Hamas, which rules the Gaza Strip, have been postponed.

The PRC is not part of the Cairo process for Palestinian unity.

Last weekend, four Palestinians were wounded in Israeli air strikes on Gaza, which came after four rockets hit southern Israel.

Since the beginning of the year, Palestinian militants in Hamas-controlled Gaza have fired more than 40 rockets at southern Israel, according to army figures.

Hamas has maintained a tacit truce with Israel, but other armed groups regularly fire rockets across the border, usually sparking retaliatory air strikes.