Canada has raised alert at its airports following intelligence reports that terrorists are trying to enter the US through the country.
Intelligence reports from British and US agencies have warned Canada that 20 Yemeni-trained terrorists are trying to enter North America, according to the Canadian Television network on Tuesday.
Canadian intelligence officials have also "gathered credible evidence that there was another group of terrorists who were also trying to get into Canada,'' the network reported.
Following the warning, Canadian airports and airlines flying to the US further raised the already high security put in place after the aborted bid to bomb a US airliner by an al-Qaeda-linked Nigerian man on Christmas day.
Prime Minister Stephen Harper met his senior ministers on Monday night to discuss the new threat to Canada and the US. Transport Minister John Baird said the government has received "two or three pieces'' of warnings about fresh terror threat to North America after the failed attempt to blow up the US airliner in Detroit.
"There is specific information that certainly causes me concern, causes our security officials concern, and I think we need to maintain heightened vigilance in this time,'' he said.
"We don't want panic. At the same time I think the public would expect us, when there is a reasonable concern, to be open and honest about that heightened concern,'' Baird added.
In the past, Americans have blamed Canada for lax security at borders, and there is still perception among many Americans that the 9/11 terrorists came from Canada.
"We are still really not over it (the perception). It is a big perception problem for Canada,'' the Canadian network said.
But there is no denying the fact the so-called Millennium Bomber Ahmed Ressam, who wanted to blow up the Los Angeles airport on the last day of 1999, had entered the US from Canada.
As the Toronto-18 terror plot - in which 18 young Muslims planned to attack the Canadian parliament and blow up other vital installations in 2006 - shows, there is increasing fear among Canadian agencies about the radicalization of some segments of the Canadian Muslim youth.
There are estimated to be more than a million Muslims in this country of 34 million, with the majority of them concentrated in the Greater Toronto Area (GTA).