(CNN) -- Bahrain on Thursday acquitted nine medical professionals who were accused of involvement in unrest in the country but upheld convictions of another 11.
All 20 were convicted last year of attempting to overthrow the government and were sentenced to lengthy prison terms.
Bahrain sliced the sentences of many whose convictions were upheld Thursday.
Of the 11 whose convictions stand, two are at large, five will be released on time served and the other four can appeal their sentences again, the Bahrain Information Affairs Authority announced.
Human rights groups and some of the medical professionals, which include doctors, say they were treating people injured in last year's protests against the government.
The group Physicians for Human Rights denounced the sentences and called on the government to set aside the verdicts against all the medics.
"Eighteen of the accused medical professionals have alleged that Bahraini security forces tortured them while in detention," the group said in a statement.
Maryam Alkhawaja, vice president of the Bahrain Center for Human Rights, tweeted that the nine acquittals should not be seen as an achievement, because "they shouldn't have been arrested and tortured to begin with."
In a statement, the government insisted that "no medic is being charged for treating protesters. The charges brought against the medics were primarily for their involvement in politicizing their profession, breaching medical ethics" and, most seriously, calling for "and involvement in the overthrow of the monarchy."
Another Bahraini doctor, Nabeel Hameed, told CNN last month that during last year's protests, "We became automatic witnesses."
He was on call -- one of only three neurosurgeons at Salmaniya Hospital, on February 18, 2011 -- when an injured protester was brought in. The patient had been shot in the head.
"For treating him and then expressing my concerns about the way he was injured, I got labeled as a traitor," Hameed told CNN's Christiane Amanpour.
Two months later, he was arrested, he said.
"They took me into an interrogation center for about four days of torture. I was not alone. I was with other doctors. They made us stand for days together ... without sleep, without toilet privileges, without anything. And in between that, you get abused, you get spat at, you got insulted ... and everybody who passes by you just beats you on the head or the back."
"But the worst thing is a room, an electronically locked room ... and when the doors open, all hell breaks loose. Because you start hearing these shouts of torture. Of people inside. ... Your turn is next. And my turn was next. ... Somebody even took a gun to my head and threatened me with death," Hameed said.
He was later released, but as a changed man, he said.
Bahraini officials have denied ordering torture.
CNN's Lucky Gold contributed to this report.