OTTAWA -- In the absence of reliable information, Ottawa is assuming that fake passports could be behind Algeria's claim that Canadians are among the al-Qaida-linked militants who took hostages at remote desert energy plant, The Canadian Press has learned.

Senior federal sources say the government is frustrated by a lack of information coming out of Algeria.

And they are unhappy that Algeria's prime minister went on television Monday and announced that two Canadian nationals were among the band of al-Qaida-linked militants who stormed a natural gas complex and took hundreds of workers hostage.

"The concern is we want to see the documentation. We want to see what proves that they're Canadian. And we want to corroborate that with back home," said one government official who was not authorized to speak publicly and requested anonymity.

"As far as we know, it's a fake passport. Until we actually see it, we won't be able to know."

Canadian officials are liaising with Algerian officials in Algiers and in Ottawa "to bring some closure to this stuff," but as of Monday night, they couldn't say when that would be.

Algerian Prime Minister Abdelmalek Sellal did not say Monday whether the Canadians were among the 29 militants killed by Algerian forces that stormed the site, or the three who were captured alive. Another 38 workers were killed.

The militants reportedly included people from Canada, and hostages who had escaped recalled hearing at least one of the militants speaking English with a North American accent.

Other reports said one of the Canadians was co-ordinating the attack. That could not be confirmed.

Sellal said the Canadians were of Arab descent. He cited a militant cell that included men from Egypt, Mali, Niger, Mauritania and Tunisia, as well as three Algerians.

The Foreign Affairs Department said it was "pursuing all appropriate channels to seek further information" and remained in close contact with Algerian authorities, but offered little else.

Asked whether Canada felt blindsided by Algerian prime minister's revelations on Monday, the official said, without elaborating: "Obviously, you'd like to be told about these things before they're announced. I think that point's been made."

Security analysts also said Monday that the Algerian government and the terrorists roaming North Africa could be fabricating the reports of Canadians among the al-Qaida linked militants.

But that doesn't mean that Canada doesn't have a live domestic security issue among some in its Algerian immigrant population, particularly in Montreal, they also said.

"Let's be careful until we actually see a body, see some documents, be able to validate those documents," said Ray Boisvert, former assistant director for intelligence at the Canadian Security Intelligence Service, Canada's spy agency.

However, Boisvert and another former senior CSIS agent, Michel Juneau-Katsuya, said it was plausible that there might be a Canadian connection to the Algerian debacle.

"The Algerian file, the North African file, has always been very important in Canada in part because we have a French community in Quebec, where they can establish themselves," Juneau-Katsuya said.

CSIS has had the Canadian Algerian community in Montreal under surveillance for decades now, he said, citing a series of high-profile cases.

The most notorious was that of Algerian-born al-Qaida member Ahmed Ressam, who was arrested in 1999 trying to enter the U.S., part of a planned attack on Los Angeles International Airport. Ressam had made Montreal his home base prior to his arrest by a U.S. border agent.

But while Canada's security apparatus may keep a close eye on certain individuals, it doesn't mean that any of those warrant arrest. And there are also thorny issues about sharing any sensitive information with certain countries, such as Algeria.

"Communication with a foreign government is always tricky. As you share the information, you don't know what the other will do with that information," said Juneau-Katsuya.

"So we've got to be careful, especially if you're dealing with an organization like the Algerian intelligence services. On allegations coming from Canada they're liable to arrest them and torture them."

Boisvert also raised the possibility that North African terrorist leader Mokhtar Belmokhtar is trying to sow havoc with forged documents.

"It could be that Belmokhtar has introduced some forged documents and put them in pockets of corpses and throw a whole bunch of people in a tizzy," he said.

"This part of the world is emerging as a new epicentre because of the Arab Spring as a driver. The place is also flush with lots of new weapons from the Libyan conflict."

"And Mokhtar Belmokhtar has lots of cash. He's a drug smuggler, people smuggler, weapon smuggler, kidnapper, and so on. He's certainly taken advantage of all that."

While the Canadian passport has been the forged document of choice for a number of dubious purposes over the years, including by the likes of Russia and Israel, Juneau-Katsuya said there's no shame for Canada if that turns out to be the case this time.

British, French and U.S. documents have also been used for nefarious purposes, he said. "Nothing is foolproof."

Even before Sellal spoke on Monday, Foreign Affairs said it was continuing to probe reports Canadians were among the hostage-takers in the bloody four-day siege that left at least 81 dead.

Private television Ennahar earlier cited security sources as saying two Canadians were among the hostage-takers and Agence France-Presse said a security source told it that it was known two Canadians were among them.

That followed reports Friday from a news agency in Mauritania, which quoted an unnamed source with the militant group who said the hostage-takers included people from Mali, Egypt, Niger, Mauritania and Canada.

Meanwhile, Foreign Affairs said this weekend it believes no Canadians or dual nationals were among the hostages, and that a permanent resident of Canada who was at the site is safe and no longer in Algeria.