Turkish riot squads fired enormous amounts of tear gas, often at close range in confined spaces, and used other types of disproportionate force in their tactics to crush the antigovernment protests that erupted last month in Istanbul, Ankara and other cities, an alliance of international medical rights groups said in a report released Friday.

The report, which cast a new light on the behavior of the Turkish police, expressed concern about what it called deliberate attacks on medical workers who had been aiding stricken protesters. The report also criticized what it described as unlawful detentions of individuals, including a prominent physician who is secretary general of the Istanbul Chamber of Medicine.

“Our investigation in Turkey confirmed that the government has been engaged in the excessive and unnecessary use of force — including using tear gas as a weapon of mass scale — which has claimed several lives and led to thousands of injuries,” Dr. Vincent Iacopino, the senior medical adviser to the Physicians for Human Rights, a Boston-based group that participated in the research and publication of the report, said in a statement on its Web site.

Dr. Iacopino and other investigators returned from Turkey last week after interviewing more than 30 health professionals, victims and witnesses to the police attacks on demonstrators.