Palestinian militants in the Gaza Strip barraged southern Israel with rockets on Friday, fraying a 5-month-old truce that has been tested sorely this week.

No injuries or damage was reported in the third successive day of hostilities, and there was no immediate military response to the rocket fire. Islamic Jihad, Gaza's second-largest militant group, claimed responsibility for the attack. The Israeli military said at least three rockets were fired.

Gaza militants and the Israeli military had largely held their fire since a June 19 truce. But the quiet was shattered Tuesday after Israeli troops launched a brief incursion into Gaza to destroy what it said was a tunnel militants had dug near the border to kidnap Israeli soldiers. Gaza's ruling Hamas group already is holding an Israeli soldier captured in a cross-border raid more than two years ago.

Click here for photos. (Warning: Graphic Content.)

Seven militants were killed during the Israeli operation and militants fired dozens of rockets in response. On Wednesday, a militant was killed in an Israeli airstrike after two rockets were fired at an Israeli town.

The attacks have provoked Israel to close its crossings into impoverished Gaza, keeping much-needed goods from reaching the coastal strip of 1.4 million people.

Although the violence is the worst since the truce took effect, neither side seems to have much to gain from a renewal of hostilities, and both Israeli and Gaza officials have said they want to restore calm.

The cease-fire dramatically curbed the near-daily rocket barrages that had severely disrupted life in Israeli border towns. Israel has not found a military solution to the rocket fire, and retaliatory strikes against Gaza militants have killed hundreds of Palestinian civilians as well as gunmen.

Hamas, meanwhile, needs the calm to strengthen its hold on Gaza, which it overtook in June 2007, and build up its arsenal ahead of a potential future battle with Israel.