An aerial view shows the Zaatari refugee camp on July 18, 2013 near the Jordanian city of Mafraq, some 8 kilometers from the Jordanian-Syrian border. (MANDEL NGAN/AFP/GETTY IMAGES)

Relief officials warned Tuesday of a brewing humanitarian crisis in southern Syria as rising violence reportedly continued to strand thousands of would-be refugees along the border with Jordan.

According to rebel officials and local residents, an intensified government bombing campaign is obstructing roads and paths in the region, where 10,000 displaced people are said to have spent the past week in border towns and villages waiting to cross into Jordan.

The U.N. refu­gee agency says the escalating violence has slowed the flow of refugees into Jordan from a high of about 2,000 a day to an average of 100 a day in recent days, prompting concerns about a massive buildup on the Syrian side.

“Every indicator inside Syria shows that the numbers of refugees should be increasing, but we are seeing the lowest figures in months,” said Andrew Harper, the agency’s representative in Jordan. “We are very concerned that Syrians in need of protection are being prevented from crossing, and this will have huge ramifications on the other side.”

Activists and Syrian rebel officials also accuse Jordan of exacerbating the crisis by changing its open-border policy. With more than 560,000 Syrians flooding into the country over the past two years, they say, Jordanian authorities have begun closing illegal crossings, citing concerns about potential infiltration by jihadists, as well as Iranian and Lebanese Hezbollah fighters.

Others say Jordan is seeking to curb the refu­gee influx because its ballooning Syrian community is already expected to cost it more than $1 billion this year and has led to overcrowding in schools and hospitals.

In recent weeks, Jordanian officials have stressed the growing social and economic strains posed by the refugee community. Before the recent drop in numbers, Jordan was taking in about 70,000 Syrians a month, a pace that U.N. officials say required the opening of a new refugee camp every 30 days.

But the greatest impact, according to Jordanian officials, has been felt outside the camps and in the towns and villages where 70 percent of the refugees reside. After a 16 percent jump in the demand for water — which increased the water deficit in arid Jordan by 50 percent — and a 20 percent jump in electricity demand, Prime Minister Abdullah Ensour recently declared northern Jordan a humanitarian “disaster zone.”

“We have been told directly and indirectly that the days of an open border are over,” said Ahmed al-Naimi, a Free Syrian Army commander who coordinates the rebel group’s refugee-crossing operations and claims that only about 10 percent of those seeking to cross into Jordan in the past month have succeeded.

“Unless a Syrian carries with him un-falsifiable proof of identity, he will be classified as a security threat and denied entry,” Naimi said.

Jordanian officials deny that their border policy has changed, noting that the kingdom continues to receive dozens of Syrians a day and attributing the drop to heavier fighting along the 230-mile-long border.

“The towns and regions which were once safe areas for refugees within Syria have become war zones,” said Brig. Gen. Hussein Zayoud, head of the Jordanian border guard, adding that the fighting has rendered more than 80 percent of the crossing points “impassable.”

“We are seeing fewer refugees reach the border, but this does not mean that the borders are closed from the Jordanian side,” he said.

Activists say dozens of local communities in Syria’s southern border areas are struggling to accommodate the would-be refugees, housing hundreds of families in schools, mosques and grocery stores even as they endure a two-week-long siege by government forces.

As a result of the siege, many Syrian border towns and villages face dwindling supplies of basic foodstuffs such as cooking oil and flour, according to residents and activists reached by phone. They warned that the sudden influx of displaced people has pushed thousands to the brink of starvation.

“We are trying to host our brothers and sisters from across Syria with dignity and respect,” said Ahmed al-Saad, a coordinator with the Local Coordination Committees, an activist network, in the border town of Tal Shihab. “But how can we feed hundreds of new families each day when we can barely feed ourselves?”

Emad al-Homsawi said he and his family of five spent nearly two weeks avoiding government checkpoints and dodging missiles while fleeing their native Homs, in central Syria.

“Now we can neither return to Homs nor continue to Jordan,” Homsawi said, speaking from a Tal Shihab bakery where his family and 20 other displaced Syrians are sheltering. “We have gone from refugees to prisoners.”

The crossing delays reportedly have proved fatal for dozens of people whose families had hoped to get them to Jordan for treatment of chronic diseases or war injuries.

Hibba al-Halabi said she could only watch as her brother Ahmed died of an infected shrapnel wound in the border village of al-Shajarah while waiting to cross Monday — an injury that she says could have been easily treated in Jordan.

“We spent two weeks traveling from Aleppo to save my brother,” Halabi said from al- Shajarah, where she has spent the past week with her family. “How many more of us must die on the border before the international community wakes up?”

Meanwhile, U.N. refu­gee officials say, the blockade has forced hundreds of other Syrians into braving more-arduous eastern routes into Jordan, trekking through the desert with little food or water.

According to the U.N. refu­gee agency, 90 percent of Syrians fleeing to Jordan over the past two weeks have taken those routes, many arriving in urgent need of medical and humanitarian assistance.

“Many of those arriving from the east have spent weeks fleeing violence, traveled hundreds of miles and arrive in really bad shape,” Harper said.

Nevertheless, Syrians say, the threats of border closures and violence will do little to slow the mass exodus in which 1.8 million people have fled their homeland for neighboring states.

“We Syrians have been left with two options,” Homsawi said. “Flee or die.”