Israel struck hard into the Gaza Strip by land and air on Friday, trading fire with gunmen in fighting that killed eight Palestinians, including a 12-year-old boy, Palestinians said.

The deaths drove the Palestinian death toll in Israeli raids to 16 since a militant attack killed two Israeli civilians at a border fuel depot Wednesday. Prime Minister Ehud Olmert has pledged to keep hitting Hamas so that it cannot "continue to operate against Israeli civilians as it does."

Gaza residents said the ground fighting appeared to be easing by Friday evening, although there was still some Palestinian rockets, and Israeli helicopter fire that killed a Hamas fighter.

The day's violence started early Friday when Israeli aircraft killed two Hamas militants in a strike near the southern Gaza town of Khan Younis, Hamas said. The Israeli military said the air force struck at gunmen near the Gaza-Israel border fence.

Around sunrise, troops crossed about a half-mile into central Gaza and battled militants just outside the Bureij refugee camp. A 12-year-old boy was shot dead and six other Palestinians were wounded during the fierce exchange of fire, Palestinian medics said.

Later in the day, in the same area, Israeli forces fired at a group of Palestinian militants who took up positions near a farm. The soldiers killed four people and wounded several, including children, witnesses and doctors said. It was unclear exactly how many of the casualties were combatants and how many were civilians.

The army said troops were involved in heavy fighting during the day but a spokeswoman did she not know about the killing of a child.

Wednesday's brazen daylight attack on the Nahal Oz terminal killed two truck drivers and prompted Israel to close the facility, which supplies all the fuel for Gaza's 1.4 million residents.

Israeli officials indicated the cutoff would not last past the weekend. An earlier Israeli plan to cut back fuel shipments in response to rocket attacks by Gaza militants was shelved under international pressure.

Hamas has ruled Gaza since June 2007, when its militants routed forces loyal to Palestinian President Mahmoud Abbas. Abbas now heads a Western-backed government based in the West Bank and is holding peace talks with Israel.

Hamas has continued attacking Israeli forces along the border and firing rockets at Israeli towns, and allows Gaza's other militant factions to do the same. It has also threatened to breach the borders with Israel and Egypt if their closure of crossings to and from Gaza continue.

In January Hamas blew several holes in the metal border wall to let hundreds of thousands of Palestinians break out of Gaza. into Egypt. Cairo has strongly warned against any attempts to forcibly open the border again and is building a heavily fortified wall along its side of the frontier.

In protests against the blockade across the Gaza Strip Friday Hamas supporters carried mockup cages, each of which contained a single banner with the word "Gaza". In one of the displays the jailer was identified as Israel, while another labelled Egypt as guarding the lockup.

Despite the ongoing violence, Olmert and Abbas have said they hope to reach a peace agreement by the end of this year and there were no signs that the latest round of bloodshed would derail talks.