OTTAWA -- A Canada-U.S. initiative to create new, cross-border, law-enforcement teams has been "postponed" due to unresolved concerns about how to treat police officers accused of breaking the law.

The so-called next-generation border project has been put off as discussions continue with U.S. officials -- almost four years after pilot projects were supposed to begin, said Staff Sgt. Julie Gagnon, a force spokeswoman.

The initiative -- part of the 2011 Canada-U.S. perimeter security pact -- would see the two countries build on joint border-policing efforts by creating integrated teams in areas such as intelligence and criminal investigations.

Two pilot projects were supposed to get underway by summer 2012.

But in 2013, it emerged that the effort was being held up by the difficult question of which country's legal system would apply if a police officer were accused of breaking the law.

In an interview, then-U.S. ambassador David Jacobson spelled out the challenges.

"If an RCMP officer is in North Dakota, and they're chasing a criminal and they go to shoot somebody, well what are the laws that govern the appropriate use of force? Is it Canadian rules? Is it American rules?" Jacobson said.

"What happens if there's a lawsuit in North Dakota? Does the Canadian RCMP officer want to be subject to litigation in the United States? We have slightly different rules," he said. "The question is: which rules are going to apply to which? It is a complicated question."

Another issue: where would a citizen of one country take allegations of ill-treatment at the hands of an officer from the other country?

A March 2015 RCMP briefing note, recently obtained under the Access to Information Act, said the Mounties should stick to their position that officers from Canada and the U.S. be treated equally "under a common criminal liability regime."

The Public Safety Department says there has been no change in the border policing project's status since the initial delay.

The perimeter security deal between the two countries, known as the Beyond the Border initiative, includes dozens of projects aimed at improving continental security while allowing low-risk passengers and goods to move easily across the 49th parallel.

The next-generation enforcement units were intended to help police strategic points along the 9,000 kilometres of shared Canada-U.S. land border.

The project was to be modelled on the Shiprider project, which involves specially trained Canadian and U.S. officers working on the water in dedicated teams.