GAZA CITY, Gaza Strip (AP) — Palestinian militants ambushed an Israeli ground force in the northern Gaza Strip on Wednesday, killing three soldiers during a day of fierce fighting. Five Palestinians were killed in separate clashes.

Despite the attack, Israel resumed fuel shipments to Gaza after a weeklong cutoff imposed in response to another deadly militant strike.

The clashes further strained Egyptian efforts to mediate a cease-fire between Israel and Hamas, which rules the Gaza Strip.

At least five Palestinians and three soldiers were wounded Wednesday’s fighting. Throughout the day, Palestinians fired rockets and mortar shells toward southern Israel, Israel’s army said, though no civilian casualties were reported.

The soldiers were killed after troops spotted two Hamas militants planting a bomb near the Israeli border. Troops pursued the militants, only to fall into an ambush by another Hamas force lying in wait, Israeli defense officials said.

The officials, who spoke on condition of anonymity because the investigation was ongoing, said the attack was not expected to lead to an escalation in Israel’s policy of targeting militants with pinpoint airstrikes and raids. Israeli leaders have repeatedly threatened a broad offensive in Gaza if militant attacks persist.

The Israeli soldiers were killed near the Nahal Oz terminal used by Israel to pump fuel into Gaza. The fuel supply was cut off last week after two Israeli civilians were killed in a Palestinian attack on the terminal — the only source of fuel for Gaza.

Hours after Wednesday’s ambush, Israel resumed fuel shipments to Gaza, Israeli and Palestinian officials said.

Mahmoud Khuzandar, deputy director of the Gaza fuel station owners’ association, said a total of eight truckloads of fuel were delivered. He said half was cooking oil, and the other half was diesel fuel for Gaza’s only power plant.

Earlier, Israeli officials had said the fuel deliveries would be delayed because of the ambush. It was not immediate clear why the decision was reversed.

The fuel deliveries were expected to provide brief relief to the Gaza Strip, though they were only a tiny fraction of what the impoverished territory needs, Khuzandar said.

Israel has been cutting back on fuel and other basic supplies allowed into Gaza for months, trying to pressure Gaza’s Islamic Hamas government to stop rocket attacks.

Without adequate fuel in Gaza, the area’s roads are mostly empty, and people rely on walking, bicycles and crammed shared taxis for transportation. Some vehicle owners in the territory have converted their cars to use cooking gas, and may be able to refuel in coming days. However, most Gazans still rely on gasoline and diesel to power their cars.

Most residents are unable to pay soaring black market prices for scarce fuel supplies. On Tuesday, the United Nations said it was gravely concerned about the effects of the fuel cutbacks.

After Wednesday’s clash, Hamas warned Israeli soldiers that they would face death, injury, kidnapping or “psychological trouble” if they raid the Gaza Strip.

“This is a letter to the Zionist enemy,” Hamas spokesman Abu Obeida said. “We will be the flaming rock upon which you will fall.”

During the fighting near Nahal Oz, two Palestinian civilians were injured when their house was hit by a tank shell in the area, medics said. The army did not comment.

In a separate incident, Israeli troops entered northern Gaza early Wednesday in what the military spokesman said was a “routine operation” to target militants launching rockets.

Troops hit gunmen at several points, the army said. Israeli aircraft also fired at a group of gunmen, the army said. Hamas said four of its fighters were killed and three wounded. Health officials said a 42-year-old farmer also was killed in an Israeli airstrike, but added that armed militants were near his vehicle at the time. The Israeli military said aircraft fire struck gunmen entering the vehicle.

Israeli armored vehicles hit and damaged a mosque, destroyed two houses and partially demolished one other, local residents said. The army said the mosque was full of explosives and exploded during an exchange of fire between troops and gunmen inside. The troops withdrew at daybreak.

Israel’s army frequently raids the Gaza Strip or launches air strikes to target militant squads that launch rockets at Israel almost daily. The crude rockets wreak panic on southern Israel and occasionally cause casualties.

Hamas, a violent group committed to Israel’s destruction, seized control of Gaza last June. Its control of the area, along with the near-daily fighting with Israel, has jeopardized Mideast peace efforts.

Israel hopes to reach a peace agreement with the moderate West Bank government of Palestinian President Mahmoud Abbas by the end of the year. But it says it will not carry out any accord until Abbas regains control of Gaza.