Pakistan: A Search for Bodies, Clues

Investigators dug through rubble looking for details, families buried their dead and a glass seller more than quadrupled his daily income on Sunday as Pakistan's capital began to clean out one day after the most powerful terrorist bomb in the country's history.

The government announced that 53 people had been killed in Saturday's bombing of the Marriott Hotel in Islamabad, which also injured more than 250 and destroyed the majority of the hotel's 300 rooms. Two Americans and the ambassador to the Czech Republic were among the dead.

In the rubble of the Marriott, a dozen vehicles sat crushed, their roofs caved in from the force of a 1,300-pound bomb. Investigators cleared out a crater 60 feet wide and 25 feet deep, large piles of mud, rocks and twisted metal sitting beside it. The lobby remained covered in debris, the former meeting point for Islamabad's elite reduced to scattered glass and marble.

Hotel On fire after bombing in Pakistan.Play

"I don't know how I'm alive," one man told ABC News while standing a few hundred feet from the blast site, where he was working when the dump truck used in the attack hit the hotel's security gates. He says he barely escaped. "God saved my life."

The Interior Ministry released footage taken moments before the explosion showing a six-wheel truck ramming into the security gate just after 8 p.m. local time. At first a dozen or so security guards back away, but they eventually try to extinguish a fire that begins in the cab of the truck. The video cuts off before the large explosion.

Security Cameras Catch Pakistani BomberPlay

"It is a direct hit on the integrity of Pakistan," Rehman Malik, the Interior Ministry chief, told ABC News in an interview late on Sunday. "We have become hostage in the hands of these terrorists."

Although no one has taken credit for the blast, al Qaeda, the Taliban and allied groups had been warning they would attack Pakistan's cities. Malik said that "all roads point to South Waziristan," the volatile tribal district along the Pakistan-Afghanistan border where senior al Qaeda leaders are believed to be hiding. Malik said the explosives included "military-grade" RDX and ammonium powder.

Earlier on Saturday, militants had ambushed two convoys in Waziristan, the first time they had launched a major attack on the military since agreeing to informal peace deals one year ago. The same militants have been blamed for making 2008 the most violent year for Western soldiers and Afghan civilians since 2001.

Security analysts here say the Taliban, al Qaeda, and their allies have never been stronger, using the Federally Administered Tribal Areas to recruit terrorists and to launch attacks in two countries. Saturday's attack was not the first time they reached deep into Pakistan's most secure areas -- and in so doing tried to influence government policy.

"I think the message is very clear," retired General Talat Masood, a former defense secretary, told ABC News. "Don't have any operations against us, military operations anywhere. Do not allow the Americans to interfere."

The United States has questioned Pakistan's willingness and ability to fight the militants, and just this month has launched at least seven ground and air assaults inside Pakistan's borders.

Asked whether he believed Pakistan was losing its battle against militants based in the tribal areas, Malik listed a series of the country's ills: "When we have so many bombings in our country, when we are losing our investment and the capital is flying, when we see our own brothers and sisters dying, when we see the children being killed, when we see the attacks from our own allies…"

But despite that, he said the government and military are dedicated to eradicating what Pakistan's President called a "cancer." "We will fight formally against them until we kill them." Malik said.

Debris from the blast site flew hundreds of feet away, including into the garden of a government building on the same street as the Marriott.

There, security guard Abid Hussein told ABC News he believes Marriott guards shot out the tires of the truck, stopping it from breaching the checkpoint and thus saving the hotel from total destruction. Hussein said was eating dinner in his guard post when he noticed a smoking garbage truck drive past his hut. Malik suggested he believed the story.

"I heard two rounds fired, then a loud noise of the tires deflating," Hussein said. "Then five more rounds, then a huge blast. I was knocked semi-conscious."

In a one mile radius around the blast site, home and business owners worked on Sunday to clean shattered panes of glass, spending hundreds of dollars -- fueling what is suddenly one of Pakistan's few growth industries.

Abdul Rehman and a small team strolled through Islamabad's main business area on Sunday evening about a quarter mile from the Marriott.

Piles of glass dotted the street, windows blown out in hundreds of stores.

He told ABC News his glass company usually makes the equivalent of $30 a day, and his workers often sit idle for hours. But today, he received calls from 8 new customers and had worked from early in the morning until sunset.

"Whatever we ask for from customers, today, they pay us," he said.

Speaking to reporters outside his hotel in the morning, the owner of the Marriott, Sadruddin Hashwani, vowed it would reopen within four months.

Despite the praise heaped on the security guards by the interior ministry, Hashwani criticized his employees and city police, calling the dump truck's presence in the center of the city a serious security lapse.

"If I were there and had seen the suicide bomber, I would have killed him. Unfortunately, they didn't," he said.