The hope that two Canadians arrested in Cairo nearly two weeks ago could soon be released was in question Thursday, after an Egyptian prosecutor failed to attend a hearing for the two to plead their case.

Dr. Tarek Loubani and filmmaker John Greyson were scheduled to meet with a prosecutor Thursday afternoon Cairo time to plead their case for release. But according to the Minister of State for foreign affairs and consular services Lynne Yelich, the hearing didn't take place.

“Canada remains deeply concerned about the cases of Dr. Loubani and Mr. Greyson and we are disappointed that the hearing scheduled for today did not take place," Yelich said in a statement released Thursday.

"We continue to work at the highest levels to confirm the specific charges against Dr. Loubani and Mr. Greyson. As we have not yet received confirmation of the charges, the Government of Canada calls for their release."

The lawyer for the two men, Adam Khaled el Shalakany, told CTV News Channel that he waited for the prosecutor outside the prison where the men are being held from 10 a.m. to 5 p.m. local time.

"The prosecution didn't show up," he said, adding that he was told the prosecution may have had an overbooked schedule.

He said he's been given no indication of when Loubani and Greyson's hearing may be rescheduled, but it will most likely take place in 15 days, as per Egyptian law. Other foreigners who were arrested around the same time also didn’t get a chance to plead their case Thursday.

The lawyeradded that he was not able to speak with his clients regarding Thursday's delay, but said he's visited them several times since their arrest and they remain in good spirits and good health.

CTV’s Daniele Hamamdjian reported Thursday night that the Tora prison where the two men are being held is overcrowded and the conditions are far from ideal.

Both Loubani and Greyson have asked for cartons of cigarettes – a common currency in prisons. Loubani has also asked for antibiotics for a fellow inmate who had an infected wound, Hamamdjian reported.

The two men were arrested in Cairo on Aug. 16, amid deadly riots that had gripped the capital and large parts of the country.

Friends and family members say the two were en route to Gaza, where Loubani was taking part in a training program at a local hospital. Greyson was reported to be researching a potential future film set in the region.

Social media campaigns have since been launched to press for their release.

Canadian officials have said that it appears as if the men were in the wrong place at the wrong time. But Egyptian prosecutors allege that the two were "participating with members of the Muslim Brotherhood" during an attack on a police station.

Deepak Obhrai, parliamentary secretary to the Foreign Affairs minister, said attempts are being made to reschedule another hearing.

“We are making all efforts to get back in touch with them and to see when the prosecutor will be there, what (the) charges (are), otherwise we are calling for their release,” he told CTV News Channel Thursday.

Greyson's sister, Cecilia Greyson, told News Channel Thursday that the delay was "disappointing."

She added that the family does not anticipate getting any additional information for at least a few days, as Egyptian weekends begin on Friday.

Justin Podur, a friend of the two men, told The Canadian Press that friends and family members won’t be deterred by the latest news.

"Despite our frustration, we are asking supporters of Tarek and John to wait for further news," he said. "But we are also aware that the prosecutor could easily extend the investigation period for another 15 days."

With files from The Canadian Press