In response to a rocket attack, Israel launched multiple air strikes on Gaza early Friday and threatened a second Gaza war if Palestinian militants do not cease their rocket attacks. The air strikes targeted what Israel said were weapons manufacturing and storage sites. Palestinians said the sites struck included workshops and a factory.

No one was killed in the air strikes or the rocket attack from Gaza on Thursday, though three children were wounded in the Israeli strike.

The air strikes come as tension has increased between Gaza and Israel recently after a period of relative calm following Israel’s three-week winter offensive in Gaza last year.

Agence France-Presse reports that Israel’s deputy prime minister, Silvan Shalom, threatened to use stronger force in Gaza if the rocket attacks do not stop.

"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.

Hamas leader in Gaza Ismail Haniya responded by blaming Israel for escalating tension and calling on the international community to end Israel’s “aggression.”

A BBC video reports that four of the air strikes hit near the area where the two Israeli soldiers were killed last week. It called the strikes the heaviest attacks since the war in Gaza last year, when more than 1,300 Palestinians and 13 Israelis died.

The Christian Science Monitor reported last month that Hamas has had difficulty stopping rocket attacks from the territory, which have been launched by extremist groups that are not loyal to the Islamist militant group that rules the coastal enclave. Israel holds Hamas responsible for any attacks from the coastal strip, and usually launches air strikes in retaliation for rocket attacks.

A Palestinian was killed during clashes with Israeli troops on March 30, and two Israeli soldiers and two Palestinian militants were killed in a gunfight on March 26. On March 18, a Palestinian rocket fired from the Gaza Strip into Israel claimed the first fatality in Israel since it launched the Gaza war last year to shut down Hamas rocket attacks. Israel says nearly 20 rockets were fired into Israel from Gaza in March, and more than 40 since the beginning of the year. Israel has repeatedly retaliated with air strikes.

Reports of the number of air strikes Israel launched Friday morning ranged from four to 13. They struck the areas of Khan Younis in southern Gaza, the Nusseirat refugee camp in central Gaza, and sites outside Gaza City. The New York Times reports that Israel claimed to have targeted sites for weapons manufacturing or storage.

Witnesses also claimed that some strikes hit areas used for militant training and a cheese factory. According to Agence France-Presse, two strikes in Khan Younis hit a site used by Hamas’s armed wing, Ezzedine Al-Qassam Brigades, while a workshop in Nusseirat was also targeted.

Palestinian news sevice Ma’an News agency reports that the sites hit included the building housing Hamas’s Al Aqsa television network in Khan Younis, a police station in the refugee camp, and a telecommunications company in central Gaza.