Twenty Bahraini medics handed long jail terms for their role during anti-regime protests launched an appeal on Sunday, authorities and a defendant said.
The doctors, nurses, and paramedics were initially tried and convicted in the military-run National Safety Court on September 28 on a raft of charges, including incitement to overthrow the regime.
They were handed sentences ranging from five to 15 years each.
The government portrayed Sunday's hearing as a new trial, following widespread condemnation of Bahrain's Sunni-led regime in the wake of last month's sentencing.
But defendants and rights activists said it was an appeal in civil court.
"Strictly speaking, this is an appeals trial. This is not a new trial," Human Right Watch's deputy Middle East director Joe Stork said, adding such politicised cases would have "the same fair trial problems as military courts."
Opposition ex-MP Matar Matar said the hearing was an attempt to "contain the international outrage" and accused the government of trying to mislead public opinion by saying the medics were being retried in civil court.
But in a dramatic reversal, the prosecutor told the court it was dropping confessions from the defendants, after medics had protested that the statements were extracted under duress.
"Although they did not drop the main charges, it is important that the public prosecution has decided to dismiss the confessions and consider them false," Matar told AFP.
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But in a telephone interview with AFP after the hearing, defendant Nada Dhaif said only two minor charges were dropped.
"But they kept the most serious charges against us," she said.
Dhaif, an oral and dental surgeon who treated the wounded in the month-long demonstrations led by the Gulf state's Shiite majority, was sentenced to 15 years in jail by the special court set up after the uprising.
A government statement later said the prosecution dropped the charges of incitement of hatred for the regime, disturbing public security through spreading false news, and the incitement of others to commit criminal acts.
It said the public prosecution will not rely on confessions to prove the remaining charges, and will use instead other evidence "including videos, physical evidence and eyewitness testimony."
"The court is not bound to follow any steps that were taken, or follow any conclusions that were reached, at the National Safety Court," it said, quoting the public prosecution.
"The public prosecution says the defendants will benefit fully from the presumption of innocence and procedural guarantees at trial in the same way as any defendant would under Bahraini law," it added.
It said representatives of the US, British and French embassies attended Sunday's hearing. The next hearing is set for November 28.
Most of the medics worked or volunteered at Salmaniya Medical Complex in Manama that was stormed by security forces in mid-March after they drove protesters out of nearby Pearl Square.