Bangladesh opposition leader Khaleda Zia was convicted of corruption and sentenced her to five years in jail on Thursday as police clashed with thousands of her supporters outside the court.
A special court found the two-time former prime minister guilty of embezzling money meant for an orphanage, a charge she had dismissed as politically motivated.
Zia, leader of the Bangladesh Nationalist Party (BNP), was convicted of embezzling about US$250,000 (Dh918,000) in donations meant for an orphanage trust established when she was last prime minister, from 2001-2006.
"This is a false and staged case. No way we will accept this verdict," BNP Secretary General Fakhrul Islam Alamgir told Agence France-Presse.
Judge Mohammed Akhtaruzzaman also sentenced Zia's son, Tarique Rahman, and four others to 10 years in prison for involvement in the crime. All can appeal their convictions.
Law Minister Anisul Huq said Zia would be imprisoned later on Thursday.
She is expected to appeal against the verdict, but it may affect her ability to stand in a general election scheduled for December.
Bangladesh law says anyone imprisoned for more than two years cannot run for office for the next five years, but Mr Huq noted that the final decision rests with the courts.
"It's up to the appeals court to decide whether she will be eligible to run," he said after the verdict.
Zia's lawyer Khandkar Mahbub Hossain said the ruling was "political vengeance" and would be overturned by a higher court.
Ahead of the hearing, police fired tear gas at thousands of activists who defied heavy security to escort the car taking Zia to the magistrates court.
The private television station Somoy said at least five police officers had been injured and two motorcycles torched during the clashes that broke out several kilometres from the court premises.
Authorities have been on high alert for days in Dhaka, where political demonstrations by Zia's centre-right BNP and its Islamist allies in 2014 and 2015 left nearly 200 people dead.
Around 3,500 party supporters and officials were arrested in a sweep by security forces ahead of the verdict, according to BNP spokesman Rizvi Ahmed.
A senior officer told Agence France-Presse more than 5,000 police had been deployed in Dhaka.
Zia, 72, is a former ally turned arch-foe of Bangladesh's Prime Minister Sheikh Hasina.
Her party boycotted 2014 polls in which Ms Hasina was re-elected but is expected to contest the next election.
Zia, who entered politics in the mid-1980s after her military dictator husband was assassinated in an abortive coup, also faces dozens of separate charges related to violence and corruption.
She has repeatedly said the charges against her are aimed at excluding her and her family from politics.
Her son Rahman lives in exile in London and was convicted of money-laundering in 2016.
Last month prosecutors sought the death penalty over his alleged role in a deadly 2004 grenade attack that injured Ms Hasina.
Zia and her son were detained by an army-backed government in 2007 and spent a year and a half in detention pending trials for alleged corruption.
"This is an attempt to use the court against me, in an effort to sideline me from politics and elections and to isolate me from the people," she told a packed news conference on Wednesday.
Human Rights Watch on Thursday urged the government to stop what it called "arbitrary arrests and detentions".
"The Bangladesh government's claims to be open and democratic ring hollow as it cracks down on political dissent," said the group's Asia director Brad Adams.
"The government has a responsibility to prevent and minimise violence, but it needs to do so in a way that respects basic rights, not flouts them."
Many private schools declared a holiday in anticipation of the verdict, while several ride-hailing services suspended operations for the day.
Police set up checkpoints at main entrances to Dhaka to prevent thousands of rural supporters of BNP and its allies from marching to the capital.
"Dhaka is effectively cut off, people in panic," read the front-page headline of the Bengali-language newspaper Prothom Alo.