Armed Islamic State extremists are expanding their influence in a sprawling camp for displaced Syrians on Jordan's border, posing a growing threat to the U.S.-allied kingdom, a senior Jordanian military commander said.

Brig. Gen. Sami Kafawin, chief of Jordan's border forces, spoke to The Associated Press during a tour of the remote desert area, just west of where Jordan, Syria and Iraq meet.

The Islamic State group seized parts of Syria and Iraq in 2014, and still holds territory there, including areas abutting Jordan, despite recent military setbacks.

A flight in a Jordanian military helicopter on Tuesday offered a view of the Rukban camp, an expanse of tents and makeshift shelters housing tens of thousands of stranded Syrians.

Conditions in Rukban and the smaller Hadalat camp deteriorated sharply after Jordan sealed its border in June, following a cross-border IS car bomb attack that killed seven Jordanian border guards.

The closure disrupted what until then had been fairly regular distributions of food and water by Jordan-based international aid agencies. In recent months, there had been mounting reports of lack of clean water, the rise of malnutrition among children and the spread of disease.

Late last year, after months of negotiations, U.N.-led aid groups and Jordanian officials worked out a new arrangement for the camps, located between two low miles-long mounds of earth, or berms, that straddle the Syrian-Jordanian border.

A food distribution center was set up several miles west of Rukban, while U.N. mobile health clinics consisting of several trailers were established on Jordanian territory, near the southernmost berm.

Aid officials said tribal leaders help organize the distributions, despite concerns by aid agencies that this will lead to unfair allotments and black marketeering.

A Syrian refugee is pictured at the Al Zaatri refugee camp in the Jordanian city of Mafraq, near the border with Syria, Reuters/Muhammad Hamed

In a joint statement on Wednesday, U.N. agencies in Jordan said conditions still "present a survival challenge," while acknowledging the Jordanian military's efforts to coordinate aid shipments.

"Delivery of humanitarian aid experienced serious delays and interruptions due to logistical and security constraints over the past months," the statement said. "Only one distribution cycle of a month's worth of food rations and essential items, including blankets, warm clothes and plastic sheeting, was made possible to those living at the berm between November 2016 and January 2017."

The statement said water has been delivered regularly and that U.N. health services were able to provide life-saving care, with the most serious cases referred to Jordan for further treatment.

On Tuesday, an AP team visited one of the health clinics, where pregnant women and young children were receiving treatment. Patients were transported from Rukban to the clinic by ambulance after security vetting.

Najah Khidr, who is two months pregnant, said she came to the clinic because she had suffered bleeding the night before. She said she and her eight-member family live in dire conditions.

"It's too cold there, no electricity and no sustainable food supplies," the 41-year-old woman said, struggling to stand up.

Another patient, 14-year-old Mathour Yassin Khleif, said a kerosene stove caught fire in his family's shelter, burning him and his sister. Khleif suffered third-degree burns, the clinic report said.

Mustafa Zboun, an official of the U.N. child agency, said most patients at the mobile clinic are children suffering from malnutrition and pregnant women.

More than 200 Syrians have been allowed entry to Jordan for medical treatment since November, he said.

At the same time, the potential IS threat from Rukban is rising, with armed militants "trying to control it and create cells inside the camp," said Kafawin, the border commander. "We are sure they have whole weapons systems."

An aerial view shows the Zaatari refugee camp, near the Jordanian city of Mafraq July 18, 2013. REUTERS/Mandel Ngan/Pool

Armed groups clash frequently in Rukban, he said. "We understand that more than 90 percent (of camp residents) are asylum seekers, but the others are extremists or Daesh people," he said, referring to IS by its Arabic acronym.

Jordan also fears an influx to southern Syria of IS militants fleeing a U.S.-backed Iraqi offensive on the city of Mosul, a former IS stronghold. The offensive began in the fall, and IS has been driven out of eastern parts of the city.

"The threat is increasing, especially in this area," Kafawin said, referring to the border stretch near Rukban. "We consider the whole Syrian border as a potential threat, but in this area, it is imminent all the time."

Pro-Western Jordan is part of a U.S.-led military coalition against the Islamic State extremists.

About half of Jordan's military personnel and resources have been deployed to protect the kingdom's borders, Kafawin said, a sharp increase from before the 2011 outbreak of the Syria conflict.