ALEPPO, Syria — If you are in the impact zone, residents here say, you don’t hear anything.

“You see the doors and the windows blow out and then they explode back in on you. You can’t even see your own fingers in front of your eyes. Some people died just from the dust,” said one survivor.

The 31-year-old asked that his name not be used as he described the moment he said a ballistic missile hit the Aleppo suburb of Ard al Hamra on Feb. 22. He was in his home three blocks away from the point of impact, but the explosion still damaged his house and killed several of his neighbors.

Following the explosion, the man joined the rescue, digging bodies and body parts from the rubble by hand. He said people had been thrown into the air by the blast, he found corpses up to three blocks from their homes.

“In this spot, right here, we heard voices under the rubble but we couldn’t get to them,” he said, pointing to a large pile of concrete debris. “We had no machines or equipment to dig through the ruins. Until a few days ago there were still dogs digging through the rubble, digging out body parts.”

For the residents of Aleppo, Syria’s largest city, this is evidence enough that the government of Syrian President Bashar al-Assad is launching ballistic missiles on civilian areas under rebel control. Rumors of ballistic missile strikes first began to circulate in December. The local Syrian Observatory for Human Rights says it has recorded 40 of them since then.

The emergencies director for Human Rights Watch, Peter Bouckaert, said his own researchers on the ground have confirmed some of those strikes. He called the development “a new low” in a conflict that has already claimed more than 70,000 lives, and displaced about 4 million others.

“Our researcher was on the ground, sometimes within hours of these ballistic missile strikes occurring, and the destruction he witnessed was staggering,” said Bouckaert, describing how entire neighborhoods had been obliterated. “We have absolutely no sign that there were any legitimate military targets in these areas, so either the government is deliberately targeting civilians or at the very least it is acting with a complete disregard for the lives of its own people.”

The International Institute of Strategic Studies reported in August 2012 that Syria had stockpiles of several types of ballistic missiles, including long-range Scuds. The Scuds believed to be in Syrian possession have firing ranges of 185 miles for the Scud-B, and up to 435 miles for the newer Scud-D models. Syrian activists say they believe the missiles were fired from the al-Nasiriyeh air base, north of Damascus, more than 200 miles away.

The Syrian government, for its part, has always denied using ballistic missiles on Syrian territory.

Human Rights Watch reported that the remnants of a missile that struck the neighborhood of Belioun in Jabal al-Zawiya, northern Syria, in December bore marks identifying it as a Luna-M ballistic missile. In a report released last month, the group concluded that ballistic missiles caused explosions at four sites in Aleppo — including Ard al Hamra — between Feb. 18 and 22.

The government’s use of such long-range missiles has made the international community nervous, particularly neighboring Turkey, which supports the Syrian opposition. The United States and Israel worry such weapons could fall into even more threatening hands, like foreign terrorist groups, if Assad eventually falls.

In its August report, “Unease grows over Syria's chemical weapons,” the International Institute of Strategic Studies said Syria — with the help of North Korea — has also been developing chemical warheads for missiles like the Scud B and C since the 1990s.

“Not only is the size of Syria's chemical-weapons stockpile a cause for international concern, but so is the variety of agents it contains,” the report read.

The report listed mustard gas, a blistering agent, and sarin, a nerve agent that causes paralysis, among Syria’s known chemical weapons supplies. Human rights groups also suspect Syrian forces have access to cyanide gas, which works as an asphyxiant, and VX — a more powerful nerve agent that lingers longer in the environment, increasing exposure rates.

These weapons can be fired using artillery rounds, chemical bombs or ballistic missile warheads. To date, there have been no confirmed reports that the government used chemical weapons against the Syrian population.

Human Rights Watch researcher Ole Solvang visited several bombing sites in Aleppo that activists believe were caused by ballistic missiles. He also investigated reports of the use of cluster bombs.

“Just when you think things can’t get any worse, the Syrian government finds ways to escalate its killing tactics,” Solvang said in his report.

Human Rights Watch released a new report on Saturday that claimed the Syrian government had used cluster bombs. The report said Syrian forces have dropped at least 156 cluster bombs in 119 different locations across the country in the past six months.

Cluster bombs take an immediate toll by dropping submunitions, or “bomblets,” across an area as large as a football field. Submunitions that fail to explode on impact can claim lives for years to come, the most common victim being children who unwittingly handle the bomblets.

More than a hundred countries have so far signed a 2008 treaty banning the use of cluster bombs. While the Syrian government is not a signatory, it denies using cluster bombs against the opposition. The United States has also not signed the treaty. In 2003, Human Rights Watch said American forces used cluster munitions during the Iraq War.

The director of the Arms Division of Human Rights Watch, Steve Goose, said the organization’s research on the ground in Syria and analysis of amateur video proves that Syrian forces are using cluster bombs.

“Syria is expanding its relentless use of cluster munitions, a banned weapon, and civilians are paying the price with their lives and limbs,” he said.