A woman stands near fire to warm herself at a refugee camp in Azaz, Syria on Dec. 17, 2012. A report released on Monday said one of the reasons many women are fleeing the country is because of incidents of rape. (Manu Brabo/AP)

Rape has become a “significant and disturbing feature” of the war in Syria, one that many refugees cite as their leading reason for fleeing the country, according to a report released Monday by a New York-based humanitarian organization.

The victims are primarily women and girls who are attacked in public, at roadblocks or at home by “armed men.” The report, by the International Rescue Committee, does not specify whether those men are primarily from government forces or from rebel ranks.

Family members are often forced to watch, according to the report, and gang rape is not uncommon. In addition, it says, there is an “alarming lack” of medical and psychological support for survivors of the attacks.

This sexual violence was “consistently identified by Syrian women, men and community leaders as a primary reason their families fled the country,” according to the report, which is based on interviews in November with refugees, officials, aid workers and others in Jordan, Turkey, Lebanon and Iraq.

The number of Syrian refugees living in neighboring countries has grown to more than 600,000. Many live in camps, while others pack into rented apartments or squat in schools, public buildings or sheds — unsafe environments that the report says can lead to sexual assaults, elevated levels of domestic violence and early or forced marriages.

In Syria, sexual-assault victims often do not report or publicize what happened for fear of retribution from their assailants or their own families, as such crimes carry a painful stigma.

“No one wants to talk about it, because in a conservative society, it is shameful to talk about it,” said Hiba Alhaji, founder of the Free Syrian Women Organization. “They don’t understand how these ladies are not to blame.”

Alhaji is based in Turkey, which has more than 150,000 registered refugees, and has tried to secure funding to start rehabilitation centers for rape victims. But she has had no luck.

Heavy fighting is continuing in Syria, particularly in the suburbs of Damascus.

On Sunday, in the northern city of Azaz, near the Turkish border, at least 20 people were killed and 99 were injured when government warplanes bombed a market, according to Doctors Without Borders, which treated many of the injured.

On Monday morning, at least five adults and eight children were killed when a house south of Damascus was hit in a government airstrike, activists said.

NATO officials said Monday that Syrian government forces fired a short-range ballistic missile over the weekend, one of more than 20 launched in the past month, according to Reuters news agency. Some of the missiles have landed close to Turkey’s border, where the United States, Germany and the Netherlands plan to install six Patriot antimissile batteries. The defense system is expected to start operating early next month, if not sooner.

Timeline: Major events in Syria’s tumultuous uprising that began in March 2011.

Suzan Haidamous contributed to this report.