Israel is methodically targeting the Hamas domain, bombing government offices, security compounds, commanders, and even Hamas-linked clinics, mosques and money changers. Yet Gaza's Islamic rulers show no sign of buckling under the aerial onslaught.

Israel says Hamas still has thousands of rockets. Hamas TV and radio remain on the air, broadcasting morale-boosting battle reports. Hamas' political and military leaders communicate from hiding places by walkie-talkie. Police patrol streets to prevent price gouging and looting.

"Israel has destroyed the buildings, but Hamas is still here," Ahmed Yousef, a Hamas spokesman, said Thursday, the sixth day of the bombing campaign. "There is no anxiety over the existence of Hamas — even if they destroy all of Gaza — because we are among the people."

Hamas' survival will depend on how far Israel is willing to go to obtain its declared objective: crippling the group's ability to fire rockets at Israeli towns and cities. Thousands of Israeli soldiers are amassed on Gaza's border, waiting for the signal to invade.

Yet Israel, which withdrew its troops from Gaza in 2005 after a 38-year occupation, also says it does not want to reoccupy the area. That suggests Hamas will be able to cling to power in Gaza, which it seized by force from moderate Palestinian President Mahmoud Abbas in June 2007.

Hamas' future also hinges on the conditions of the cease-fire that will eventually be brokered.

The group's leaders are demanding that Gaza's borders be opened in exchange for calm; the territory has been largely sealed off by Israel and Egypt since the Hamas takeover. A plan promoted by Egypt and the U.S. would link any opening of the borders to giving Abbas a new foothold in Gaza.

With Hamas losing much of its infrastructure to the Israeli assault, it might be more willing to cut a deal with Abbas, said Gaza analyst Emad Falluji, a former Hamas activist.

For now, Hamas has proven surprisingly resilient.

Since the offensive began, the group's fighters have fired nearly 400 mortar shells, homemade rockets and Iranian-supplied Grad rockets, according to the Israeli military. It has struck two new targets closer to Israel's center, the southern cities of Ashdod and Beersheba. Four Israelis have been killed.

Hamas has thousands more rockets in its arsenal, said Maj. Avital Leibovich, an Israeli army spokeswoman. Most of the weaponry has been smuggled in through some 300 tunnels under the Gaza-Egypt border, including about 300 tons of explosives imported in the last three years, she said.

Israel has destroyed about a third of the tunnels, along with explosives and missiles stored in basements and mosques, Leibovich said. That has hurt Hamas' ability to fire rockets, but hasn't crippled it, she said.

Israeli Vice Premier Haim Ramon said the bombing would continue. "Hamas has suffered a lot," he said. "We have hit its military infrastructure, its government infrastructure, its tunnels. We still have a lot of targets to attack in coming days."

Israel is also hunting Hamas' political and military leaders.

On Thursday, a warplane dropped a one-ton bomb on the house of Hamas strongman Nizar Rayan, killing him, his four wives and 10 of his 12 children. Rayan, among Hamas' top five leaders in Gaza, had taken few precautions in recent days, even appearing in public, unlike other prominent Hamas figures who have gone into hiding.

Hamas has had years to prepare for battle with Israel, particularly after Israeli troops pulled out of the territory more than three years ago.

The group has dug bunkers and tunnels, copying tactics of the Hezbollah militia in Lebanon, another ally of Iran, Leibovich said.

One of Hamas' other trump cards is an Israeli soldier, Gilad Schalit, who was captured by Hamas-allied militants in a cross-border raid in 2006.

The initial round of Israeli bombing wiped out key police installations, and Hamas officials say 185 members of the group's security forces are among the nearly 400 dead. Hamas security men have slipped into civilian clothes to avoid being targeted, but still patrol the streets. Hamas' Al Aqsa TV and radio have broadcast a toll-free number for residents to make criminal complaints.

Policemen direct traffic and run checkpoints near bombed-out government buildings to prevent scavenging. They tour gas stations, bakeries and groceries to make sure owners don't take advantage of growing shortages to hike prices.

On Tuesday, two Hamas plainclothes police officers drove up to a small gas station in Gaza City and learned from customers that the price for diesel fuel had tripled. They approached the owner who swiftly lowered the price.

Hamas inspectors with scales visit bakers, making sure that the government-fixed price for bread — 55 pitas for 7 shekels, about $2 — is being honored.

Hamas leaders say the militant movement is able to keep fighting.

"Our spirits are high, because Israel has failed to reach its target," said Hamas legislator Mushir al-Masri. "They conducted powerful strikes in the first few days, but in reality Hamas is stronger, we rose from the rubble and hit places we've never hit before."