Canada and the U.S. have signed an agreement that paves the way for the militaries from either nation to send troops across each other's borders during an emergency, but some are questioning why the Harper government has kept silent on the deal.

Neither the Canadian government nor the Canadian Forces announced the new agreement, which was signed Feb. 14 in Texas.

The U.S. military's Northern Command, however, publicized the agreement with a statement outlining how its top officer, Gen. Gene Renuart, and Canadian Lt.-Gen. Marc Dumais, head of Canada Command, signed the plan, which allows the military from one nation to support the armed forces of the other nation during a civil emergency.

The new agreement has been greeted with suspicion by the left wing in Canada and the right wing in the U.S.

The left-leaning Council of Canadians, which is campaigning against what it calls the increasing integration of the U.S. and Canadian militaries, is raising concerns about the deal.

"It's kind of a trend when it comes to issues of Canada-U.S. relations and contentious issues like military integration. We see that this government is reluctant to disclose information to Canadians that is readily available on American and Mexican websites," said Stuart Trew, a researcher with the Council of Canadians.

Trew said there is potential for the agreement to militarize civilian responses to emergency incidents. He noted that work is also underway for the two nations to put in place a joint plan to protect common infrastructure such as roadways and oil pipelines.

"Are we going to see (U.S.) troops on our soil for minor potential threats to a pipeline or a road?" he asked.

Trew also noted the U.S. military does not allow its soldiers to operate under foreign command so there are questions about who controls American forces if they are requested for service in Canada. "We don't know the answers because the government doesn't want to even announce the plan," he said.

But Canada Command spokesman Commander David Scanlon said it will be up to civilian authorities in both countries on whether military assistance is requested or even used.

He said the agreement is "benign" and simply sets the stage for military-to-military co-operation if the governments approve.

"But there's no agreement to allow troops to come in," he said. "It facilitates planning and co-ordination between the two militaries. The 'allow' piece is entirely up to the two governments."

If U.S. forces were to come into Canada they would be under tactical control of the Canadian Forces but still under the command of the U.S. military, Scanlon added.

News of the deal, and the allegation it was kept secret in Canada, is already making the rounds on left-wing blogs and Internet sites as an example of the dangers of the growing integration between the two militaries.

On right-wing blogs in the U.S. it is being used as evidence of a plan for a "North American union" where foreign troops, not bound by U.S. laws, could be used by the American federal government to override local authorities.

"Co-operative militaries on Home Soil!" notes one website. "The next time your town has a 'national emergency,' don't be surprised if Canadian soldiers respond. And remember - Canadian military aren't bound by posse comitatus."

Posse comitatus is a U.S. law that prohibits the use of federal troops from conducting law enforcement duties on domestic soil unless approved by Congress.

Scanlon said there was no intent to keep the agreement secret on the Canadian side of the border. He noted it will be reported on in the Canadian Forces newspaper next week and that publication will be put on the Internet.

Scanlon said the actual agreement hasn't been released to the public as that requires approval from both nations. That decision has not yet been taken, he added.