The US has demanded the release of Egyptian opposition leader Ayman Nour, hours after he was given a five-year jail term for forgery.
Egypt has rejected claims that the charges were political
The White House said it was "deeply troubled" by the conviction of Nour, who is on hunger strike.
Nour, who came second in a presidential poll in September, was accused of falsifying signatures to register his party, Ghad.
Egypt has previously denied claims that the charges were politically motivated.
But the US, a key ally of Egypt, said the outcome cast doubt on Cairo's democratic credentials.
"The conviction of Mr Nour, the runner-up in Egypt's 2005 presidential elections, calls into question Egypt's commitment to democracy, freedom, and the rule of law," White House spokesman Scott McClellan said in a statement.
"The United States calls upon the Egyptian government to act under the laws of Egypt in the spirit of its professed desire for increased political openness and dialogue within Egyptian society, and out of humanitarian concern, to release Mr Nour from detention."
At the court, hundreds of Nour's supporters shouted slogans against President Hosni Mubarak as the verdict was given.
"Hosni Mubarak's rule is illegal! The trial is illegal!" they chanted.
Riot police were on standby in nearby streets but there were no reports of disturbances.
Nour has been in hospital after starting the hunger strike earlier this month in protest at his detention.
His lawyer, Amir Salim, is quoted by the Associated Press news agency as saying the decision against him will "go into the dustbin of history".
"This is a political verdict that will be annulled by the appeal court," he said.
A co-defendant in the trial, Ayman Ismail, had admitted forging documents for Nour - but later withdrew his testimony, saying the confession was forced out of him with threats against his family.