About 3,000 people lined up outside the H1N1 vaccination clinic at the Olympic Oval in Calgary on Saturday morning. (Peter Akman/CBC)

Alberta health officials said Saturday the province's H1N1 immunization clinics have been suspended immediately because of a national reduction in the number of available vaccine doses.

Officials said they will roll out a plan early next week for targeted H1N1 vaccines, focusing only on those at the greatest risk. Mass immunizations likely will not resume for at least a few weeks.

Targeted recipients are pregnant women, children six months to five years of age, people under 65 with chronic health conditions, people living in remote and isolated communities and health-care workers.

Alberta Health Services' senior medical health officer Dr. Gerry Predy said the details of the targeted immunization clinics will be released Monday.

He said the suspension of mass immunizations is in effect until further notice.

"It is important for the public not to panic and to respect the priorities for vaccination," Predy said.

"Again, we're asking people to be calm. There will be more vaccine and there should be enough vaccine for everybody who wants it."

The announcement comes after H1N1 vaccination clinics in Edmonton and Calgary were overwhelmed Saturday, forcing clinics to close their lineups and turn people away.

Thousands of people showed up looking for vaccines, some lining up as early as 4 a.m.

At the Olympic Oval in Calgary, more than 3,000 people lined up.

By the time the clinic was shut down early Saturday morning, officials said the wait had already reached an estimated eight hours and the lineup stretched about half a kilometre outside the building.

Mass vaccinations still right call: officials

Health officials continued to defend their decision to offer mass vaccinations instead of targeting high-risk groups as most others provinces did.

"Our pandemic plan was to vaccinate as many people as possible in as short a period of time as possible, and we always did ask the priority groups to come forward first," Predy said.

"The difficulty with screening in a mass clinic was it would put a lot of onus on our staff to then turn people away ... In retrospect, we still believe it was the right thing to do given the information we had at the time we developed the plan."

Predy said demand for the H1N1 vaccine during the first week of the immunization campaign was tremendous.

More than 300,000 Albertans were vaccinated, but he said the province could not continue to meet that level of demand with the expected reduction in the vaccine shipment next week.

Starting Monday, supplies to all parts of Canada will slow while the manufacturer focuses on a non-adjuvant vaccine, meant as an option for pregnant women. An adjuvant boosts effectiveness but can have unwanted side-effects.

A total of 14 people have died from swine flu in Alberta.