U.S. troops could find themselves on Canadian territory helping police and firefighters deal with emergencies under a new pact signed by the two countries.

The new accord says that soldiers from either country could cross the border, but would then be under the command of the host country.

Defence Minister John McCallum said the pact recognizes that threats such as those posed by terrorists or biological agents don't recognize international borders, and continues a long tradition of Canada-U.S. co-operation on dealing with common threats.

John McCallum
John McCallum

The agreement creates a new binational planning group that will draw up plans for deploying military and civilian forces in the event of emergency, including terrorist attacks and natural disasters.

The armed forces would be called in to assist the firefighters, paramedics and police who would be on the front lines of any emergency response.

The planning group will be headed up by Canadian Lt.-Gen. Ken Pennie and include 15-20 military officers from the Canadian and American forces. A number of civilian officials will also be included, McCallum said.

Pennie is currently deputy commander of the North American Aerospace Defence Command, or Norad.

The planning group would co-ordinate joint maritime surveillance, intelligence sharing, and military exercises.

McCallum and Foreign Affairs Minister Bill Graham insisted the plan protects and enhances Canadian sovereignty rather than posing a threat to it.

"The planning group ... (puts) Canada in a position to work with the United States on plans to defend North America, plans the United States would otherwise be developing without us," McCallum said.

U.S. forces would only cross the border if Canada requested them, and they would be under Canadian operational command. The planning group would have no forces at its own disposal to deploy.

"Nothing would happen without the go-ahead from the national capitals," Graham told CBC Newsworld.

Canada's air force is already closely integrated with the U.S. defence of continental airspace under Norad.