|Sannikov was found guilty of organising mass disturbances, a charge he had denied [EPA]
One of the main political opponents of Alexander Lukashenko, the Belarus president, has been sentenced to five years in a high-security jail after being convicted of helping to organise a rally against the leader's re-election.
Andrei Sannikov, a former deputy foreign minister and co-founder of the Charter 97 rights group, was found guilty of organising mass disturbances, a charge he had denied.
Sannikov, 57, was the first to be sentenced of five presidential candidates who are standing trial in Minsk for their part in a mass protest on December 19, the day Lukashenko was re-elected to a fourth term in power.
The crackdown on the rally, which was followed by mass arrests of dissidents and opposition activists, triggered US and European Union sanctions against Lukashenko, including a travel ban on him and his circle.
The political opposition says the re-election of Lukashenko, in power in the ex-Soviet republic since 1994, was fraudulent and Western monitors have described it as "flawed".
The US condemned Saturday's decision as a "politically motivated" conviction.
"The United States condemns the May 14 conviction of presidential candidate Andrei Sannikov and other democratic activists in Belarus," Mark Toner, state department spokesman, said in a statement.
"We consider the five presidential candidates... and other activists, who are being tried after being arrested as part of the crackdown related to the December 19 presidential elections, to be political prisoners."
In a statement, Guido Westerwelle, the German foreign minister, said: "In this trial, justice has not been served. It is the political will of Lukashenko that was executed.
"I condemn with the strongest terms the judgements against Andrei Sannikov and the other opposition supporters.
"The government must immediately review all judgements that had a political motivation. All political prisoners must be freed.
"The people of Belarus also have the right to live in freedom and dignity."
Wife on trial
The state prosecutor had asked for a seven-year jail term to be handed down on Sannikov for the offence, which carries a maximum of 15 years in jail.
| Sannikov's wife, journalist Irina Khalip, is also on trial over her part in the protest [Reuters]
Sannikov received the lowest jail sentence allowed by law for the offence.
"Sannikov is guilty of organising mass disturbances, accompanied by violence against the person, attacks, destruction of property ... he led a crowd that committed excesses," said presiding judge Natalya Chetvertakova, reading the sentence.
After the judge delivered the verdict and sentence, Sannikov smiled from inside the cage where he was being held with four co-accused.
"The main thing is to protect my family!" he called out to supporters. Some supporters jumped up and shouted "Glory to the heroes!".
A group of about 10 men chanted "Freedom!"
Four other opposition activists being tried with Sannikov were sentenced to jail terms of between three and 3 and a half years.
"They [the authorities] have run over our family like a steam-roller," said Sannikov's mother, Alla Sannikova, in tears in the court's corridors.
Sannikov's wife, journalist Irina Khalip, is also on trial over her part in the protest and sentence is due to be passed on her on Monday; the prosecutor has asked for a two-year suspended sentence.
The family has expressed fear that the couple's four-year-old son could be taken into state care if they are both jailed.
The trials coincide with a severe currency crisis in the ex-Soviet republic in which the national currency, the Belarussian rouble, has plunged against the dollar.
The threat of devaluation has led to a shortage of imported goods in shops and people are hoarding food staples such as vegetable oil and sugar to hedge against hard times.
Analysts say the economic crisis is pushing Belarus towards its old Soviet master, Russia, on whom it relies for energy imports.
Moscow last week refused to put up a loan of $1bn which Minsk had been counting on to help it overcome the crisis.