The verdicts on Monday from two trials in the Uzbek capital, Tashkent, bring to 73 the number of people sentenced behind closed doors over the mass bloodshed in the eastern province of Andijan in what human rights groups say was a brutal crackdown by authorities.
A written statement from Uzbekistan's supreme court read: "The defendants were found guilty of carrying out premeditated murders in aggravating circumstances, terrorist acts, mass riots and a range of serious and very serious crimes."
Twenty-five men were sentenced last week in closed proceedings to between 12 and 22 years in jail, and last month 15 other defendants received sentences ranging from 14 to 20 years after proceedings dismissed by critics as reminiscent of Stalin-era show trials.
Russian news agencies earlier reported that the Uzbek authorities had charged 121 people over the uprising, which would mean 48 are still awaiting trial.
The Uzbek authorities say 187 people were killed in the 13 May violence, blaming it all on the actions of Islamic insurgents who took over parts of the city.
But witnesses and human rights groups say hundreds of people died after troops opened fire on unarmed civilians who took to the streets to demonstrate against the government.
Meanwhile, Amnesty International said Germany is bound by international law to investigate Uzbekistan's interior minister, who is in hospital in Germany, over the crushing of the protests and torture allegations.
Zakirdzhon Almatov has been granted permission to have a life-saving operation in Germany despite being barred from the European Union.
The EU said the ban was "aimed at those individuals who are directly responsible for the indiscriminate and disproportionate use of force" to put down the protests in Andijan.
Barbara Lochbihler, general-secretary of Amnesty in Germany, said Kay Nehm, the federal prosecutor, was obliged to investigate and, if necessary, issue an arrest warrant for Almatov.
"A systematic attack against civilians represents a crime against humanity"
general-secretary of Amnesty International in Germany
Lochbihler said in a statement: "A systematic attack against civilians represents a crime against humanity."
Germany was also bound under United Nations rules to examine allegations of systematic torture levelled at the Uzbek authorities, the statement said.
"Every Uzbek who is arrested can expect to be tortured or mistreated. Confessions are often extracted under torture which are then used in unfair trials as the sole basis for long jail or death sentences," Lochbihler said.
The Federal Prosecutor's office was not available for comment.
Witnesses of the protests said troops opened fire on a crowd of men, women and children in the main square in the town, killing more than 500 people.