OTTAWA -- Conservative Leader Stephen Harper cited security concerns on Tuesday for his refusal to commit to doing more to help refugees from the Middle East.

As provinces pledged their own funds to help alleviate the crisis, Harper deflected a question about whether he would send more staff to the region to help an already over-stretched bureaucracy.

Security is paramount and every potential refugee needs careful screening, Harper said.

"We cannot open the floodgates and airlift tens of thousands of refugees out of a terrorist war zone without proper process," Harper said in a Facebook question and answer session. "That is too great a risk for Canada."

Screening refugees is partially done through data such as digital photographs, fingerprints and other biometric data. Visa officers in Beirut began using biometrics in November 2014 but struggled to get going, according to documents obtained under Access to Information.

"This process is frustrating, labour intensive and takes a long time to complete," a Foreign Affairs program manager in Beirut reported on Day 1 of the new system, expressing hope that it would get faster as they got more familiar with the process.

The biometrics program kicked in as officials scrambled to meet a deadline the Conservative government had imposed in July 2013 in its first formal commitment to Syrian refugees: Resettle 1,300 people by the end of 2014. They didn't meet the target until March 2015.

A second commitment, to resettle 10,000 over three years, appears to be moving faster. At the end of July, 1,002 people had arrived and by Sept. 3, the number was up to 1,074.

The Conservatives promised in August to admit a further 10,000 if elected, with a focus on religious minority groups. In the Syrian context, that means mostly Christians.

The cascading commitments to Middle East refugees have strained the resources of Citizenship and Immigration for years.

The first major challenge was a government decision to shutter the Canadian embassy in Damascus for security reasons in 2011. That left hundreds of files in limbo as staff in embassies in Jordan and Egypt were handed most of the responsibility for the program run out of Syria.

At that point, officials were primarily coping with requests from Syrians already in Canada to get their relatives out under the family-reunification program, as well as with a 2009 commitment to resettle 20,000 Iraqis by the end of 2015.

The embassies then were able to hire more local staff and bring Canadian civil servants in from elsewhere, but it still took until July 2013 to get through the backlog of family cases alone, documents show.

The Immigration department says on its website that it can take between 11 months to four years for a private group to sponsor a refugee through visa offices in the Middle East. A spokesperson said Syrian applications are now being handled through its office in Winnipeg and are processed within a year.

"It is important to remember that exactly how quickly applications can be processed in the future will depend on the volume of applications, security situation in the region and how quickly requirements such as security screening and medical examinations can be completed," Nancy Caron said in an email.

The campaigning New Democrats are promising more staff as well as to set up a Syrian refugee co-ordinator position to oversee those efforts, saying it would cost $74 million to resettle 10,000 refugees this year, and $63.8 million annually to resettle 9,000 refugees each year until 2019.

The Liberals have pledged an additional $100 million this fiscal year for refugee processing as well as for sponsorship and settlement services in Canada.

Most of the refugees now arriving in Canada are coming thanks to private groups, part of the reform of the system that has seen the government offload more resettlement onto the private sector. The government has said it did so because refugees have a better chance at successful integration if they arrive with community ties.

Financial records on the Immigration department's website also show the changes have saved the government at least $3.3 million.