The army said the first of approximately 90 trucks had started to deliver medicine, fuel, cooking gas and other vital goods into Gaza. The shipment includes a large donation of goods from Egyptian President Hosni Mubarak's wife.
Israel's Defense Ministry agreed to open its cargo crossings into Gaza as part of its policy of avoiding a humanitarian crisis there. Defense Minister Ehud Barak said the decision came after consultations with defense officials as well as calls from the international community.
Israel had originally agreed to open the cargo crossings with Gaza on Wednesday, but shut the passages when Gaza militants began pummeling southern Israeli towns with more than 80 rockets and mortars. The barrage was the heaviest since before an Egyptian-mediated six-month-long truce between Israel and Gaza's Hamas rulers took effect in June.
The army said nine mortars were fired toward Israel early Friday. No injuries were reported.
Israel has maintained a strict blockade of Gaza since the June 19 cease-fire began unraveling six weeks ago, allowing in only small quantities of essential goods. Egypt has also sealed its border crossing with the territory, which is Gaza's main gateway to the outside world.
Israeli Foreign Minister Tzipi Livni was in Cairo Thursday for meetings with Mubarak, who urged Israel to exercise restraint in its response to the rocket fire. Israeli leaders have been issuing threats and Prime Minister Ehud Olmert even issued a direct, emotional plea to the people of Gaza to stop firing and turn against their Hamas leaders whom he called "the main reason for your suffering for all of ours."
Olmert told the Arabic-language Al-Arabiya TV that Israel would not hesitate to respond with force if attacks continued. "I am telling them now, it may be the last minute, I'm telling them stop it. We are stronger," he said.
Israel left Gaza in 2005 after a 38-year occupation. Islamic Hamas militants seized control of Gaza in June 2007, after routing security forces loyal to Western-backed Palestinian President Mahmoud Abbas.
Israel has thus far been reluctant to press ahead with a campaign likely to exact heavy casualties on both sides. Past incursions have not halted the barrages, and officials fear anything short of a reoccupation of Gaza would fail to achieve the desired results.
Israel is expected to continue its military consultations over the weekend.
Also Friday, a poll published in the Maariv daily showed Livni's Kadima Party inching ahead of its main rival Likud for the first time ahead of Feb. 10 elections.
A Teleseker survey showed Kadima winning 30 of parliament's 120 seats, to Likud's 29 seats. The poll surveyed more than 800 people and had a margin of error of 2 seats.