Israel on Friday threatened a widescale military operation against the Gaza Strip after a string of air strikes which injured three Palestinian children following rocket attacks from the enclave.

Israel's deputy prime minister, Silvan Shalom, warned that the military would soon launch a new offensive on the Hamas-ruled Gaza Strip unless the rocket fire was halted.

"If this rocket fire against Israel does not stop, it seems we will have to raise the level of our activity and step up our actions against Hamas," Shalom told public radio.

"We won't allow frightened children to again be raised in bomb shelters and so, in the end, it will force us to launch another military operation," said the deputy premier.

"I hope we can avoid it, but it is one of the options we have, and if we don't have a choice, we will use it in the near future," he said.

Three Palestinian children -- aged two, four and 11 -- were hit by flying glass in one of the six overnight raids, said Moawiya Hassanein, head of the Palestinian emergency services in Gaza.

There were no other reports of casualties.

The head of the Islamist Hamas movement's government in the Gaza Strip, Ismail Haniya, reacted by blaming the Jewish state for the increase in tensions.

"We call on the international community to intervene to stop this escalation and Israeli aggression," Haniya said in a statement.

The strikes came after a rocket fired by Palestinian militants landed near the southern Israeli city of Ashkelon late on Thursday, causing damage but no casualties, the army said.

Nearly 20 rockets have been fired into Israel in the past month, including one that killed a Thai farm worker, in the worst spate of violence since the end of Israel's 22-day assault on the territory launched in December 2008.

Since the war, which killed some 1,400 Palestinians and 13 Israelis, Israel has routinely responded to sporadic rocket fire with air raids against smuggling tunnels and workshops which Israel says are used to make rockets.

Three of the Israeli strikes overnight targeted an area near Khan Yunis, in southern Gaza. Two of the missiles hit a guard post of Hamas's armed wing, the Ezzedine Al-Qassam Brigades.

A fourth raid destroyed a workshop in the refugee camp of Nusseirat, in central Gaza, according to Hamas and witnesses.

In two other air raids, Israeli fighter planes targeted points in the west of Gaza City, destroying a small dairy factory in the Sabra district, according to witnesses.

The military said it hit "a weapons manufacturing site in the northern Gaza Strip, a weapons manufacturing site in the central Gaza Strip and two weapons storage facilities in the southern Gaza Strip."

"The (army) holds Hamas as solely responsible for maintaining peace and quiet in the Gaza Strip," it said.

The rise in rocket fire comes amid mounting tensions in the region sparked by Arab fears that Israel has been moving to deepen its hold on annexed, mainly Arab east Jerusalem.

It has also been accompanied by fresh clashes along the Gaza-Israel border.

On Tuesday, a Palestinian teenager was killed and several others were wounded as Israeli troops fired on protesters near the border of the blockaded territory.

And two Israeli soldiers, including an officer, were killed along with two Palestinian gunmen during fierce clashes last weekend when Israeli tanks carried out a brief incursion into Gaza.