ISRAELI forces pounded dozens of targets and edged closer to the northern edge of Gaza City today, killing 15 militants in heavy fighting as southern Israel enjoyed one of its quietest nights since the military began its offensive against the Islamic Hamas group two weeks ago.

The Israeli military said its aircraft attacked more than 40 targets throughout Gaza, striking 10 rocket-launching sites, weapons-storage facilities, smuggling tunnels, an anti-aircraft missile launcher and gunmen. It said ground forces inside Gaza also engaged militants in a series of ground clashes. Flames and smoke could be seen rising into the sky over Gaza City.

The fighting raged after both Israel and Hamas ignored a UN resolution calling for an immediate cease-fire. Israel has dismissed Thursday's UN Security Council resolution as impractical, while Hamas, whose government in Gaza is not recognized internationally, is angry it was not consulted about the diplomatic efforts.

Some of the heaviest fighting Saturday occurred on the strategic coastal road north of Gaza City, Palestinian security officials said. Israeli forces moved to within about one mile (1.5 kilometers) of the city, before pulling back slightly. While Israel has largely taken control of the road, militants continue to operate from hidden positions in the area. The road is often used to fire rockets into Israel or attack Israeli navy boats off the Mediterranean coast.

The army said it killed 15 militants during Saturday fighting. Palestinian hospital officials confirmed only four deaths, but fighting has hindered paramedics from collecting bodies and treating the wounded.

Israel launched the offensive on December 27 to halt years of Palestinian rocket attacks on southern Israel. A week later, ground troops moved in, with artillery and tank fire that has contributed to a surge in civilian casualties. Palestinian medical officials say more than 800 Palestinians have been killed, roughly half of them civilians. Thirteen Israelis have been killed _ four of them by militant rockets, the rest in battle in Gaza.

In a possible sign of progress for the military, no rockets were fired into Israel overnight, a sharp drop from the dozens of projectiles that were launched in the early days of the offensive.

Israeli military officials cautioned against reading too much into the lull, and by this morning, several rockets had landed in uninhabited areas of southern Israel.

The offensive has caused extensive damage throughout Gaza, fueling fears of an impending humanitarian crisis. Chris Gunness, a spokesman for the UN agency for Palestinian refugees, said roughly two-thirds of Gaza's 1.4 million people are without electricity, and half don't have running water.

He said the UN planned to distribute food and medicine from its existing supplies today. But he said a halt on aid shipments into Gaza through Israel-controlled border crossings _ imposed Thursday after a UN truck driver was shot and killed by Israel _ remained in effect. It was unclear when the deliveries will resume.

"As each day goes by, and for each moment that the cease-fire demanded by the Security Council is not observed, the crisis continues," he said.

In Israel's first official response to the UN resolution, Prime Minister Ehud Olmert's office said more Hamas rockets fired Friday "only prove that the UN's decision is not practical and will not be kept in practice by the Palestinian murder organizations."

Senior Cabinet ministers issued a statement saying the military offensive would continue until rocket fire from the Hamas-ruled territory ends. Hamas, which receives backing from Iran and Syria, has improved its capabilities to the point that roughly one-eighth of Israel's 7 million citizens now live in rocket range.

UN Secretary-General Ban Ki-moon spoke with Olmert by phone and Friday and told the prime minister that he was disappointed the violence was continuing in disregard of the resolution, according to Ban's office.

Hamas also dismissed the resolution, and spokesmen expressed annoyance they were not consulted.

"Nobody consulted Hamas or talked to Hamas. Nobody put Hamas in the picture and yet Hamas is required to accept it. This is unacceptable," Mohammed Nazzal, a senior Hamas official based in Syria, told Al-Arabiya television.

Israel says any cease-fire must include assurances that Hamas will halt attacks and end the smuggling of weapons into Gaza through the porous Egyptian border.

Hamas has said it won't accept any cease-fire deal that does not include the full opening of Gaza's border crossings. The UN resolution emphasized the need to open all crossings, which Israel and Egypt have kept sealed since Hamas militants forcibly seized control of the territory 18 months ago.

Israeli leaders oppose that step because it would allow Hamas to strengthen its hold on Gaza.

The foreign minister in the Western-backed government of President Mahmoud Abbas, which was driven out of Gaza by the rival Hamas in 2007, criticized both Israel and Hamas for not accepting the demand for a halt to fighting.

"Both have responded to the resolution in the same way, in total disrespect," Riad Malki said at UN headquarters in New York. He said the Security Council should enforce its resolution, perhaps by levying sanctions.

The rising civilian death toll has drawn heavy criticism of Israel from international aid groups and triggered anger throughout the Islamic world and elsewhere. There have been daily protests in the Middle East and in Europe, where there also has been a rise in anti-Semitic attacks.

In Washington, Secretary of State Condoleezza Rice said it is difficult to protect civilians in a place as densely populated as Gaza _ an area just 25 miles (40 kilometers) long and roughly six miles (10 kilometers) wide.

"It's also an area in which Hamas participates in activities like human shields and using buildings that are not designated as military buildings to hide their fighters," she told reporters. "So it's hard."

The Security Council resolution called for an immediate, durable and fully respected cease-fire, leading to the full withdrawal of Israeli troops from Gaza.

While the call was tantamount to a demand on Israel and Hamas to stop fighting, it did not require that Israel's troops withdraw until there was a durable cease-fire.

The resolution also urged UN member states to intensify efforts to provide guarantees in Gaza to sustain a lasting truce, including prevention of arms smuggling _ a key Israeli concern.

A six-month truce unraveled in November, and Israeli officials have said that lull allowed Hamas to bring in more advanced weaponry through hundreds of smuggling tunnels snaking beneath the Gaza border from Egypt's Sinai Desert.

Seven Hamas officials crossed into Egypt on Friday through the Gaza border crossing at Rafah, on their way to Cairo for Egyptian-hosted negotiations on a truce with Israel.

The talks were expected to begin sometime Saturday following the arrival of a Hamas delegation from Syria, including politburo members Mohammed Nasr and Imad al-Alami.

Despite the cool reception to the Security Council vote, the foreign ministers of Germany and Spain planned to visit the region to promote the UN resolution.