Aug 13 (Reuters) - Alberta backtracked on Friday on plans to lift its remaining COVID-19 restrictions, as hospitalizations and infections rose in the Western Canadian province just weeks before students return to school. Alberta, which already has among the fewest coronavirus-related restrictions in Canada, had planned to lift on Monday requirements that infected persons must self-isolate and that riders in buses and taxis must wear masks. The provincial government will defer those changes until at least Sept. 27. It will also extend testing outside of doctors" offices to the same date. The province decided to act after seeing 62% more hospitalizationscurrently than it expected and as COVID-19 cases among children emerge in the United States due to the Delta variant, said Dr. Deena Hinshaw, Alberta"s chief medical officer of health. The pace at which Alberta has moved to lift restrictions has generated sharp criticism from doctors and parents. "I am sorry that the way I communicated these changes caused distress," Hinshaw said. Students will return to the classroom across Canada in September, after a year in which the pandemic forced many schools to adopt virtual learning. The online approach limited spread of the virus, but put stress on parents. COVID-19 cases are rising in Canada after provinces lifted most economic restrictions this summer, but active cases, around 15,000, are less than one-fifth the record high reached in spring, according to public health data. Alberta, governed by Premier Jason Kenney"s United Conservative Party, has the highest rate of active COVID-19 cases among the 10 provinces, with 93 per 100,000 people infected. The province will reopen schools with no restrictions, other than requiring masks on school buses, Education Minister Adriana LaGrange said. In Ontario, Canada"s most populous province, students, except those in kindergarten, must wear masks indoors. Schools in Quebec, the country"s second most populous province, will not require students to don masks in the classroom or practice social distancing. Manitoba and Saskatchewan, two other Western Canadian provinces, will not require students to wear masks.