Ten years ago this Sunday, Winnipeggers came together to help 1,500 passengers diverted to the city when air travel was grounded after the 9-11 terrorist attacks.

A commemorative plaque was given from the U.S. on Friday to mark the occasion.

"We don't say it often enough sometimes how grateful we are for Canada and Manitoba in standing by us," said Tim Chipullo, U.S. consul.

Hundreds of planes were diverted across Canada in response to the 9-11 attacks.

Now, Canadians are being asked to help in another way.

"For a security agency, a national security agency, to detect something is happening to an individual in a particular part of the country in some basement, in front of the computer, is quite difficult," said Vic Toews, public safety minister with the federal government.

Toews said the threat of homegrown terrorists is on the rise.

Manitoba's Islamic community is one group working with police to learn how to spot signs.

"We are doing what we can because security of Canada is our security," said Shahina Siddiqui, president of the Islamic Social Services Association.

Siddiqui also points to the gunman attack this summer in Norway, suggesting Canadians should remember individuals from all backgrounds can be influenced by radicalization.

RCMP said the signs of radicalization are similar to those when people are being recruited into gangs, including they become distant and school grades can be affected if the person is a student.

More information is available on the RCMP's website at:

http://www.rcmp-grc.gc.ca/pubs/nsci-ecrsn/radical-eng.htm

Officials in New York and Washington have increased security after learning that al-Qaeda may be planning another attack in those cities, as the 10th anniversary of 9-11 approaches.

Canada Border Services also advises there is a potential for delays at crossings between the U.S. and Canada and travelers are advised to plan ahead and avoid traveling during peak times.

- with a report from CTV's Caroline Barghout