Dr. Adam Kushner agreed to go to Syria last month to help in any way he was needed. And when the Baltimore surgeon got there, the work was waiting for him.

In the hours before he arrived at a small hospital in the northern province of Aleppo, a nearby village had been attacked. He walked in to find rows of wounded, his new colleagues already at work stabilizing and treating them.

"It was in the middle of a mass casualty," said Kushner, who visited Syria last month with the group Doctors Without Borders. "I immediately put my pack down, put on a pair of scrubs, and started helping."

Such episodes have become common in Syria, where more than two years of violent conflict between the government and opposition fighters have ravaged a health system once among the most advanced in the Middle East.

While the Obama administration rallies support for a military strike against the regime of President Bashar Assad, aid groups are warning that health conditions in the country of 22 million are deteriorating.

Sixty percent of Syria's hospitals have little or no capacity, the World Health Organization said this week, and more than half of the country's ambulances are out of service. In the most violent areas, the U.N. agency said, health professionals are unable to report to work.

It isn't only emergency services that have been affected. Disruptions in vaccination programs, overcrowding in public shelters and damage to communal water and sanitation systems have increased the risk of infectious disease, the agency reported. Shortages in essential medicines for chronic diseases mean patients with hypertension, diabetes, cancer, epilepsy, asthma and renal failure lack access to treatment.

Three million Syrians have fled their homes, and 2 million have left the country for Turkey, Lebanon, Jordan, Iraq and other neighbors.

The World Food Programme says a surge in violence and the proliferation of military checkpoints is interfering with its distribution of aid. The U.N. agency says it was able to send food to only 2.4 million of the 3 million Syrians it planned to feed last month. It appealed this week for more access to the needy inside the country.

Doctors Without Borders operates six hospitals and four health clinics in Syria, and supports another 27 hospitals and 56 medical posts. Christopher Stokes, general director of the Geneva-based organization, described a "catastrophic humanitarian situation, characterized by extreme violence, displacement, and deliberate destruction of medical facilities.

"In the case of such extreme violations of humanitarian law," he said, "humanitarian assistance cannot respond effectively and becomes meaningless itself."

Doctors are among the few outsiders still traveling to Syria. Kushner, an associate in the international health department at the Johns Hopkins Bloomberg School of Public Health and a faculty member of its Center for Refugee and Disaster Response, is one of several area physicians who have made brief visits since the fighting began.

Kushner was in Baltimore on the morning of Aug. 8 when he opened an email from Doctors Without Borders asking for a surgeon to help in Syria.

The general surgeon, who has worked in Africa, Asia, Latin America and the Middle East, had visited Lebanon for the organization early last year to assess the likely surgical needs of Syrians inside and out of the country.

He discussed the email with his wife, a resident in gynecology and obstetrics at Hopkins who has also worked in international aid. By evening, he was on a plane bound for Brussels, and a briefing. Within two days of receiving the email, he was walking into a field hospital in Aleppo.

Kushner declined to comment on the civil war in Syria, or on the Obama administration's plans to join the fray.

He focused instead on what he saw during his eight days working as one of two surgeons in the hospital set up by Doctors Without Borders: patients unable to get sufficient treatment for chronic conditions such as diabetes, hypertension and heart disease, with periodic influxes of wounded.

He arrived in the midst of one such influx.

"We saw people coming in with shrapnel wounds and bullet wounds," he said. "This had been going on for about a week or so."

He said the great majority of the wounded were civilians.