OTTAWA — The Liberal government revealed Tuesday that its promise to resettle 25,000 Syrian refugees will take longer and cost more than originally planned.

Rather than bring that many people in by year's end, the resettlement process will now be split in two, with 10,000 to arrive by Dec. 31 and the remainder by the end of February.

But specific details of how that will be accomplished are unclear, with government officials unable to say when mass arrivals of refugees will begin, where they'll go after landing in Toronto or Montreal, whether the military will in fact be called upon to assist or the final cost.

The decision to abandon original year-end deadline to resettle the entire 25,000 was due to nothing more than a need to institute the best possible program, Immigration Minister John McCallum said.

"I've heard Canadians across the country say 'yes, you have to do it right and if it takes a little bit longer to do it right than take the extra time'," he said.

"When we welcome our newcomer friends with a smile, a smile alone is not sufficient."

The first group will be made up largely of privately sponsored refugees, whose files, in many cases, have been in the works for months as churches and other community groups moved to assist some of the most vulnerable people fleeing the Syrian civil war.

For the component to be brought in by government, Canadian officials are working with the United Nations High Commissioner for Refugees to select people from Jordan and Lebanon. They will work with the Turkish government to find suitable candidates from that country.

Priority for government refugees will be given to complete families, women at risk, members of sexual minorities and single men only if they are identified as gay, bisexual or transgender or are travelling as part of a family.

Private sponsors have no restrictions on whom they can bring over.

More than 500 officials have been assigned to work on the massive resettlement program.

All health and security screening will take place overseas and will involve multiple assessments and the collection of biometrics.

Under regular immigration screening, a file that has some security concerns is sent for more detailed review, but in this instance, any red flags on the first pass will result in that person's case being set aside entirely in order to speed the process, said Public Safety Minister Ralph Goodale.

"Right from day one, our plan was to be diligent," Goodale said.

Once screening is complete, refugees will be flown to Toronto and Montreal, largely on chartered aircraft though the military is also on call to provide airlift every 48 hours if necessary. What it would take to engage them in that role is unclear.

From there, they will be spread across 36 different destination cities which already have resettlement programs in place. The government did not provide a list, although it said about one third are in Quebec. Temporary accommodation will be provided by the military if required, but the government aims to have lodging in place in the host cities and towns.

The program will cost the federal government an estimated $678 million over the next six years but that doesn't include additional funding that could be necessary for provinces and territories. It does include transportation costs for the privately-sponsored refugees; usually, their hosts bear that financial burden.

At Tuesday's briefing, the government also did not address whether it intends to meet the campaign promise to give $100 million to the United Nations to assist its resettlement efforts.

Conservative Immigration critic Michelle Rempel said abandoning the end-of-year timeline was the right move, but concerns remain.

"It's one thing to inspire Canadians, it's another thing to be accountable to them with accurate plans and with accurate costing," she said.

The NDP noted that the planned cost is far higher than the $250 million the Liberals budgeted for in their platform and said they hope the details will be ironed out moving forward.

During the election campaign, the Liberals initially promised to resettle 25,000 people by government means alone.

After they were sworn into office, they clarified that meeting the year-end deadline would involve both government and privately sponsored refugees.

McCallum said the 25,000 number still stands and the resettlement of Syrian refugees will continue after February until that many government-assisted refugees are in the country.

Since January, just over 3,000 Syrian refugees have arrived in Canada as part of previous government commitments. But the Liberals said Tuesday those who arrived prior to Nov. 4, 2015 will not be counted as being among the 25,000.

Since that date, about 100 Syrians have arrived in Canada.

Since the outbreak of the war in Syria in 2011, the UN estimates some 4.2 million people have been displaced.

Stephanie Levitz, The Canadian Press