Israeli forces on Thursday killed seven Palestinians, including a schoolteacher, in its campaign to stop daily rocket barrages from the Gaza Strip, while adding new economic pressure — approving a symbolic cut in electricity for the beleaguered territory.

Israeli Defense Minister Ehud Barak vowed even harsher military action if Gaza militants persist with their rocket fire at southern Israel. "If the [rocket] fire continues, we will intensify our activity and the other side's losses, until we resolve the [rocket] problem," he said.

In one incident, an Israeli rocket hit a field school, killing the teacher. News footage showed there was a rocket launcher near the school.

Alongside its military strikes, Israel is ratcheting up its punitive measures against Gaza, hoping to push the population to stop militants from firing rockets at Israel. Beyond daily airstrikes and less frequent ground operations, Israel's latest move is to begin cutting back on the flow of electricity to Gaza.

The first cutback, a symbolic one of less than one percent of the electricity Israel supplies, was expected later Thursday, after approval from the Defense Ministry was obtained. Gaza generates about a quarter of its own electricity at a plant run on fuel imported from Israel. The rest comes over 10 electricity lines directly from Israel and one from Egypt.

Human rights groups have complained that measures like cutting back on fuel and power are collective punishment, harming innocent civilians. While imposing the limits, Israel insists it will not cause a humanitarian crisis in Gaza.

Deputy Defense Minister Matan Vilnai said Thursday that Israel would make the maximum cuts possible. "We will continue to pressure the Gaza Strip, but not in a way that will harm their minimum needs. They won't get anything beyond that," he told Army Radio.

A fuel cutoff last month led Hamas to shut down the Gaza City power plant in a well publicized event, causing blackouts in most of Gaza City and embarrassing Israel, which resumed some fuel shipments within days. Then Hamas broke down the Egypt border wall on Jan. 23, giving hundreds of thousands of Gazans a brief taste of freedom until Egypt closed the breaches 12 days later.

Israeli Foreign Minister Tzipi Livni said Thursday the Gaza rocket fire must factor into Israeli-Palestinian peace negotiations, restarted at a U.S.-sponsored Mideast conference in November.

"A real response must be given to the threats from the Gaza Strip prior to the establishment of a Palestinian state," she told U.S. envoy James Jones, her office said. She added that Israeli security is a "basic condition of any peace agreement."

Seven rockets were fired at southern Israel on Thursday morning, the military said. One landed in the yard of a home in the rocket-scarred town of Sderot, slightly wounding one person.

The Israeli military released film Thursday showing 3-foot-wide holes dug into the soft Gaza earth, launching silos to protect rockets from Israeli airstrikes. The military said Gaza militants learned the technique from Hezbollah guerrillas in Lebanon.

Though the small, homemade rockets cause little damage and few serious casualties, thousands of Israeli communities around Gaza have been traumatized by the constant explosions.

In Israeli operations Thursday against the rocket squads, a 38-year-old Palestinian teacher was killed Thursday when an Israeli surface-to-surface missile struck an agricultural school in the northern town of Beit Hanoun.

Associated Press Television News video showed the school to be a group of huts in a rural area. An APTN cameraman saw a rocket launching device among olive trees, indicating militants had used the school's planting area for cover to launch attacks. He was unable to photograph the launcher.

The Israeli military said it aimed at a group of rocket launchers and denied firing at a school.

The fighting erupted earlier in the day after Israeli tanks drove several hundred yards into northern Gaza. Hamas militants and Israel troops traded automatic fire, as Israeli 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 the Hamas military wing. The Islamic Jihad faction said one of its militants also died in the clash.

Another Palestinian militant died of wounds from an airstrike a day earlier in the northern Gaza Strip, Hamas said.