The military-backed interim government in Bangladesh has detained former Prime Minister Khaleda Zia and her son.
Khaleda Zia is also facing charges of tax evasion
Ms Zia was refused bail in a Dhaka court and jailed to await trial, her lawyer said. She faces charges of extortion and corruption.
Her lawyer said he suspected her arrest was politically motivated.
Hours earlier, new corruption charges were made against another former Prime Minister, Sheikh Hasina, who is already accused of extortion and murder.
Bangladesh has been under emergency rule since January, when the interim government cancelled elections. It has banned most political activity.
The interim government has arrested 150 politicians in what it says is a crackdown on corruption.
But one of her lawyers, Abdul Wadud Khandakerm, said Ms Zia's arrest was aimed at forcing her out of politics.
"She told the court that the case was fabricated, motivated, conspiratorial and fictitious," he said, adding that Ms Zia would return stronger than before.
Ms Zia and her younger son, Arafat Rahman Coco, were led to court amid tight security after being arrested at her home at 0730 (0130 GMT).
Hundreds of police surrounded the court and thousands of Zia supporters gathered outside.
Security forces had surrounded the home since midnight (1800 GMT Sunday).
Ms Zia - leader of the Bangladesh Nationalist Party - is facing charges of corruption and abuse of power for allegedly using her influence to determine the operators of two state container depots in 2003, during her second term as prime minister.
Mr Coco is accused of pushing his mother to approve the deal. He is still being questioned by police and will remain in custody for seven days, lawyer Rafiqul Islam Miah said.
Eleven others are also named in the case, brought by Bangladesh's Anti-Corruption Commission.
Ms Zia - who stepped down as prime minister in October 2006 - is also facing criminal charges connected with earlier tax evasion allegations.
On Sunday, the anti-corruption commission filed charges against Ms Zia's bitter rival Sheikh Hasina, the head of the Awami League, accusing her of taking illegal payments from a private electricity firm totalling $435,000 (£215,000).
Sheikh Hasina was arrested in July
The commission said Sheikh Hasina had taken the money when she was in power between 1996 and 2000.
Sheikh Hasina denies all charges against her. She has been in custody since July.
Six other people, including former senior officials, have also been charged.
This is the first charge brought against Sheikh Hasina by a government body, so is seen to carry more weight than the others, says the BBC's Mark Dummett in Dhaka.
Sheikh Hasina is being held in a house in the parliament complex.