– The Associated Press

GAZA CITY, Gaza Strip – Israeli military shelling aimed at Palestinian militants missed its target Tuesday, killing three children and their uncle and wounding 13 other family members as they played soccer in their backyard in the Gaza Strip, Palestinian officials said.

The attack, which Israel said was a mortar strike, was launched in response to repeated rocket fire toward Israel. It dramatically escalated a recent round of simmering violence with Palestinian militants and threatened to set off the first heavy fighting in more than two years. Israel and Gaza’s ruling Hamas militant group have largely observed a cease-fire since an Israeli military offensive ended early 2009.

The Israeli military acknowledged civilians were killed but said it was aiming at Palestinian militants who had launched seven mortar shells against Israel earlier Tuesday. They exploded in open areas causing no injuries.

Lt. Col. Avital Leibovich, an Israeli military spokeswoman, said the army did not know that civilians were in the area at the time of the strike and stressed that Israel had no desire to raise tensions and hoped that Hamas also didn’t have that intention. “We never operate when civilians are identified,” she said.

On Tuesday evening, an Israeli airstrike also targeted a group of militants about to launch mortar shells. Islamic Jihad said three of its militants were killed and another was injured.