The backdrop to the latest explosion of violence in the Gaza Strip: skeletons of unfinished apartment towers, shuttered factories, empty store shelves and skyrocketing prices for bread and cigarettes.

Five months of rule by the Islamic militants of Hamas and isolation from the world have taken a heavy toll on the already impoverished territory, and frustration over the hardship helped drive this week's mass rally by the rival Fatah movement that ended in mayhem.

Still, Hamas' grip on power doesn't appear in serious danger. Heavily armed and backed by Iran, it remains entrenched despite months of international sanctions.

The group showed its willingness to use considerable force to stay in power when Hamas police opened fire during Monday's rally of more than 250,000 people. By the end of the day, seven civilians were dead and 85 wounded. Hamas then rounded up 400 Fatah activists overnight and threatened "additional steps" against its bitter enemy.

Economic decline has been rapid since Hamas seized Gaza by force in June and Israel closed the territory's borders in an unprecedented lockdown. Most factories have closed, tens of thousands lost their jobs and exports and most imports are frozen.

Roughly 75 percent of the 1.5 million Gazans now live in poverty, up more than 10 points from the summer, according to Palestinian government officials in the West Bank.

Rami Kehail, 37, said he joined Monday's Fatah march even though he doesn't support the movement led by moderate Palestinian President Mahmoud Abbas and voted for Hamas in the 2006 parliamentary election won by the militants.

"The number of people who came out was a kind of referendum," said Kehail, partner in a construction company that since June has had to lay off all but one of its 50 employees because the border closure keeps all cement out of Gaza. "It was a sign of loathing of our reality."

Hanan Ashrawi, an independent legislator in the Fatah-controlled West Bank, said she believes Gazans cannot be ruled by force indefinitely. "The Palestinian people in Gaza will gradually ... hold Hamas to account," she said.

An independent Palestinian polling firm, the Jerusalem Media and Communications Center, said this week that support for Hamas among Palestinians fell from 30 percent to 20 percent over the past year. Fatah's support rose from nearly 31 percent to 40 percent.

Both this year's and last year's survey interviewed 1,200 adults and had a margin of error of three percentage points. Two-thirds of those surveyed were in the West Bank, in keeping with the relative populations of the two Palestinian territories, but the results on support for Fatah or Hamas were not substantially different in the two areas.

Gazans say they are down to their last reserves.

Supermarket owner Mohammed Abu Sultan, 30, has only two boxes of candles left, so his customers in the Shati refugee camp will soon have to sit in the dark during frequent power outages. He's also low on cleaning products, diapers and sugar substitutes for diabetics.

"By the end of the month, we will have sold everything," he said.

Talaat al-Ghul, 47, said he spends his days fishing because he cannot bear to look at his building block factory, which used to support 10 workers and their large families, but has been idle since June.

Even if the borders were to reopen, he'd need $3,000 to restart production. Rust is eating away at his two cement block presses and the forklift has a flat tire.

"This has taken me back 10 years," said the father of 11, who started his modest business a decade ago with the help of a small loan from the United Nations.

Near al-Ghul's factory, the gray skeletons of eight unfinished apartment towers stand near the beach, wind blowing through the holes where windows should be.

The apartments, 40 per tower, have already been sold, but the tenants can't move in and are now paying double — a mortgage for the new homes and rent for the apartments where they live now.

Construction sites across Gaza have shut down because of lack of raw materials, mainly cement, and contractors have laid off 35,000 laborers.

Building engineer Alaa Abu Zeina, 48, said Gaza's future is bleak. He laughed at assurances by Ismail Haniyeh, head of the Hamas government, that God will somehow provide for Gaza.

"As Haniyeh said, patience, patience, patience, that's the solution," Abu Zeina said sarcastically. "And then God is going to rain cement on us."

Israel's border clampdown, along with a threat to scale back fuel and electricity deliveries, seeks to pressure Hamas into halting rocket and other cross-border fire at Israeli border towns. Israeli leaders also intend it as a signal that Israel will eventually sever all ties with the territory, from which it withdrew in 2005.

However, Gaza militants are undeterred. The Israeli army says more than 1,200 rockets and mortar shells have been fired toward Israel since June.

Hamas continues to bring in millions in cash through smuggling tunnels under the Egypt-Gaza border, enough to pay salaries to 16,000 members of its security forces and government employees.

"They will keep the resources that they have for themselves," Gaza economist Omar Shaban said of Hamas members.

While Hamas takes care of its own, Shaban said, the border closure has been a severe blow for Gaza's already anemic economy, and the misery is providing fertile ground for extremists.

"People will not die from hunger, but you will find people who are frustrated, who want to leave this country, or who are ready to sell themselves to any extreme party," he said.

Israel says that no nation can sit by as rockets rain down on its territory and that economic pressure is preferable to reoccupying Gaza. Israel says a military offensive is a last resort, because of the expected heavy loss of life and uncertain outcome. Previous military operations did not root out militants or halt rockets.

"For us it's a case of damned if you do, damned if you don't," said Miri Eisin, an Israeli government spokeswoman. "We tried a lot of varieties, but with none of them the rockets ever stopped."

Israel says it is doing its best to prevent a humanitarian crisis. A few dozen Gazans a day are let into Israel for medical treatment. Israel allows in 10 basic items — cooking oil, salt, rice, sugar, wheat, dairy products, frozen vegetables, frozen meat, medical equipment and medicine.

Human rights groups say the squeeze is worsening, though, particularly since Israel designated Gaza a "hostile territory" in September.

Months of border closures have taken their toll, said John Ging, local head of the U.N. Relief and Works Agency, which provides aid to some 870,000 people in Gaza.

"People are trying to cope with survival at a basic level," he said.