Seven Palestinians were killed Thursday, including six militants, in an Israel Defense Forces operation in the northern Gaza Strip, as Gaza militants fired at least seven Qassam rockets at southern Israel.

One of the rockets struck a building in the western Negev town of Sderot, and a civilian was treated for shock.

Two of the rockets hit open areas in the Sha'ar Hanegev Regional Council, causing no damage or injuries.

The fighting in the Strip erupted earlier in the day after IDF tanks drove several hundred meters into northern Gaza. Hamas militants and IDF troops traded automatic fire, as Israel Air Force aircraft fired missiles and Hamas lobbed mortar shells.

Five Hamas men were killed, three by missiles and two by gunfire, said Abu Obeida, a spokesman for Hamas' military wing. Two were field commanders, he said. The Islamic Jihad faction said one of its militants also died in the clash.

Palestinian medics confirmed that six bodies were removed from the area.

Another Palestinian militant died of wounds on Thursday that he sustained in an airstrike a day earlier in the northern Gaza Strip, Hamas said.

Local residents said IDF tanks and heavy bulldozers penetrated the border fence near the town of Jabaliya in the coastal territory.

The teacher was killed, and two other staffers were hurt, when an IDF surface-to-surface missile struck an agricultural school in the northern town of Beit Hanun, Hamas said. It released no further details, and school officials weren't immediately available for comment.

The IDF, which frequently operates in Beit Hanun against Palestinian rocket squads, said it opened fire in the area at a group of rocket launchers. "We definitely did not fire at a school," an IDF spokeswoman said, adding that the military was looking into the report.

IDF troops completed the operation and withdrew from Palestinian territory before noon on Thursday, Israel Radio reported.

The fighting came a day after Palestinian militants from the Gaza Strip launched at least 10 Qassam rockets into Israel, lightly wounding a two-year-old and 12-year-old girl.

Late Wednesday, the IAF aircraft also carried out three strikes in Gaza wounding some four Hamas men, according to Israel Radio. The first hit a metal workshop in central Gaza, wounding no one, Hamas said.