Byline: the CNN Wire Staff
(CNN) -- A protest in solidarity with 13 people convicted of plotting to overthrow the government in Bahrain led to arrests in the capital Friday, state media said.
Six protesters were accused of participating in rioting and sabotage, according to the Bahrain News Agency.
Authorities used tear gas on protesters, who had defied the government's refusal to let them demonstrate, according to the opposition.
"Regime forces turned the capital, Manama, to a military barracks where troops deployed heavily armed," according to Bahrain's main opposition group, Al Wefaq. "The regime's forces suppressed masses destined for the capital to participate in the massive mass rally called for by opposition today."
The country's Interior Ministry accused the arrested protesters of "terrorizing innocent people and traders, sparking panic and blocking roads," the state news agency reported. The ministry also said it "had taken legal action against Al Wefaq and referred the case to the public prosecution."
The ministry said it held Al Wefaq responsible for encouraging acts of violence and sabotage.
The government said it had denied the protesters permission to demonstrate because of potential major traffic delays in an important business corridor.
On Tuesday, a Bahrain appeals court upheld all verdicts against 13 defendants accused of plotting to overthrow the regime and breaching the constitution, authorities said.
Seven of the sentences upheld were for life in prison, and one of the people sentenced was Abdulhadi al-Khawajah, a prominent activist who ended a 110-day hunger strike earlier this year.
The court reduced the sentence of a 14th defendant to five years and convicted six others, Bahrain's Information Affairs Authority said.
The defendants were arrested for their roles in anti-government demonstrations last year as the Arab Spring movement swept across the region.
Demonstrations in Bahrain failed to gain the traction of other Arab Spring uprisings after a crackdown by authorities in the island state, backed by troops from nearby Saudi Arabia and the United Arab Emirates.
Last November, Bahrain's Independent Commission of Inquiry issued a report critical of authorities' reactions to the protests, which began in February 2011, spurred by uprisings in Tunisia and Egypt.
Bahrain plays a key strategic role in the Middle East and is home to the U.S. Navy's Fifth Fleet headquarters.
The U.S. State Department said it was "deeply troubled" by the court's decision.
"We call on the government of Bahrain to investigate all reports of torture, including those made by the defendants, as it has pledged to do, and to hold accountable those found responsible," State Department spokesman Patrick Ventrell said in a written statement.
Amnesty International called the upholding of the sentences "outrageous."
"Today's court decision is another blow to justice and it shows once more that the Bahraini authorities are not on the path of reform but seem rather driven by vindictiveness," said Hassiba Hadj Sahraoui, deputy director of Amnesty International's Middle East and North Africa Program.
The government defended the court's procedures and decisions, saying it "provided all assurances of a fair trial." It noted that Amnesty International was one of the international entities that attended the trial.
It said the defendants may appeal their sentences to the Supreme Court.