NATO has imposed tough new restrictions on foreign journalists covering the war in southern Afghanistan, changes that could affect how much Canadians see and hear from war-torn Kandahar.

The new measures, imposed in early March, mirror the way the U.S. military manages reporters in Iraq.

The restrictions make it virtually impossible for Canadian journalists to leave Kandahar Airfield on their own to interview local Afghans and return unimpeded to the safety of NATO's principal base.

Last month, Canadian soldiers were required to escort newly arrived journalists everywhere on the airfield, including to the dining hall and showers.

A photographer from the Reuters news agency and a handful of Canadian journalists, were escorted between buildings and confined to their sleeping quarters when not working.

The practice has been temporarily suspended under pressure from the Canadian military, which has tried unsuccessfully to have the overall policy reversed.

Some of the new rules do not apply to American journalists because the measures would violate their rights under the U.S. constitution.

A Canadian defence critic and an organization that represents journalists condemned the new rules, accusing the U.S. of trying to shut down Canadian coverage.

"The media is not the enemy and this is a form of censorship – and it is unacceptable," Liberal MP Denis Coderre said Tuesday.

"There is a public interest to know what's going on in the field."

The new rules came as Washington prepared to deliver an additional 21,000 combat soldiers and trainers to the country to confront the revived Taliban insurgency.

Security officials at Kandahar Airfield, including the base commander, declined to comment on the measures.