JERUSALEM, July 19 (Xinhua) -- Gaza militants fired a mortar shell at southern Israel on Thursday, retaliating earlier Israeli fire which killed a member of Hamas' military arm, officials and media said.

Sirens heard in the regional council of Eshkol in southern Israel on Thursday afternoon. The military said in a statement that one mortar bomb exploded near a cowshed.

No injuries or damage were immediately reported.

A military spokesperson said that in response, a tank targeted an observation post belonging to Hamas, the Islamist Palestinian organization that runs Gaza, in the southern Gaza Strip.

Earlier Thursday, Palestinian media reported that Israeli fire killed a Hamas operative and injured three others.

After the attack, two mortars were fired at a military force which was near the fence between Israel and the besieged Palestinian enclave.

Israel recently said it would not allow the continuation of the sending of kites and balloons with combustion materials, which have consumed at least 34,000 dunams. Prime Minister Benjamin Netanyahu threatened that the army will take a stronger military action in Gaza if the launching of arson balloons will continue.

The violence was part of a recent escalation in the region, which started on March 30 with rallies to protest the crippling blockade that Israel has been imposing on Gaza since 2007. Israel reacted to the protest with fire, killing at least 134 Palestinians.