JERUSALEM — Israel on Tuesday launched an unusually heavy series of airstrikes on Gaza in retaliation for Palestinian rocket attacks, raising the prospect of a new round of bloody fighting after a relative lull for two years.

The military said the Israeli strikes hit seven different targets in Gaza. Palestinian officials said eight militants were wounded. Then the Palestinians fired another rocket at southern Israel, lightly wounding a 16-year-old Israeli girl.

The violence followed the deaths of five Gaza militants Saturday in the deadliest Israeli assault on the coastal strip in months, indicating a trend of escalation. Two years ago, incessant rocket barrages from Gaza led Israel to launch a punishing three-week invasion that left more than 1,400 Palestinians dead, including many civilians.

In another sign of increasing tension, the Israeli military chief, Lt. Gen. Gabi Ashkenazi, said Tuesday's strikes were the first to target Gaza's ruling Hamas since the invasion. The military said the attacks were in response to the firing of 13 rockets and mortars at Israel over the past week.

Appearing before parliament's foreign affairs and defense committee, he described the situation as potentially "fragile and explosive."

Until recently, militant attacks from Gaza had subsided dramatically since Israel's offensive in late 2008,

Although Hamas, the Islamic militant group that rules Gaza, has limited attacks on Israel since then, Israel holds the group responsible for all attacks from the territory. A number of smaller militant groups have continued to fire rockets and mortars.

The military said Tuesday's airstrikes targeted a weapons factory and smuggling tunnels. It said some of the tunnels were designed to allow militants to infiltrate into Israel.

Palestinians said one of the sites hit was a government-built dairy factory.

The violence added to tensions in the region stemming from the impasse in peace efforts.

Unlike Hamas, which remains committed to Israel's destruction, the rival, Western-backed Palestinian government in the West Bank supports peace talks with Israel. The U.S.-backed talks have broken down over the issue of Israeli settlement construction in the West Bank.

With negotiations at a standstill, the Palestinians have launched a campaign for international recognition of a Palestinian state in the absence of a peace deal with Israel.

Israel's Foreign Ministry said Tuesday that its diplomats will actively fight the Palestinian initiative. Spokesman Yigal Palmor said Israel believes peace talks are the only way forward.

"The envoys will talk to diplomats and journalists to get Israel's views across," he said.

Further reflecting Israeli-Palestinian tensions, Israel on Tuesday approved a multimillion dollar plan to renovate Herodian, a key West Bank historical site, sparking Palestinian objections.

Herodian was a winter palace of King Herod, ruler of the Holy Land from 37 to 4 B.C. Israel said it would invest about $4.5 million to restore the site because of its connection to Jewish heritage. Herod expanded the Second Jewish Temple in Jerusalem.

Palestinian Authority spokesman Ghassan Khatib said West Bank sites are Palestinian heritage, not Israeli, and that such moves deepen tensions.

Israel included some West Bank sites, including Herodian, in a list of national heritage sites in February. Palestinians protested, and the U.S. called the list "provocative."