Sheikh Hasina, the former prime minister of Bangladesh, has been arrested in the country's capital Dhaka and remanded to police custody.
Khaleda Zia, Hasina's main political rival and another former leader, was also ordered to appear in court on tax evasion charges as part of the military-backed interim government's crackdown on corruption.
Hasina was ordered into jail for an unspecified period ahead of a trial on charges of extorting money from a businessman, defence lawyer Abdul Matin Khasru said on Monday.
Denial
She was denied bail. Khasru said Hasina has been accused of extorting around $441,000 from a company in return for allowing it to build a power station while she was in office.
Hasina has denied all the charges against her, saying they are aimed at keeping her from contesting the next elections.
Local television broadcast images of hundreds of security force members surrounding Hasina's residence.
Meanwhile Khaleda Zia's lawyer said "the Dhaka metropolitan magistrates' court issued a summons on Monday against Khaleda Zia and 10 others for failing to pay taxes for a company that she owns."
Mohammad Sanaullah said Zia, who led Bangladesh twice from 1991-1996 and again from 2001-2006, must appear by August 26.
Bangladesh is still under a state of emergency imposed by an army-backed interim administration which took charge in January.
The government launched a crackdown on politicians ahead of elections planned for late next year and Hasina has been barred from leaving the country.
Political violence
In April, police charged Hasina with abetting in the murder of four political opponents, and a court issued a warrant for her arrest on that charge but it was later withdrawn.
The charge involved the deaths of four protesters during a riot in October at one of a series of demonstrations by her Awami League party.
A bitter feud between the country's two major political camps - led by Hasina and her archrival and another former prime minister Khaleda Zia - ahead of scheduled elections earlier this year led to weeks of deadly street protests in which 34 people were killed.
The violence forced the interim government tasked with overseeing the elections to cancel the polls and declare a state of emergency.
PHOTO CAPTION
Bangladeshi riot police stand guard in front of the residence of former prime minister Sheikh Hasina Wajed during her arrest in Dhaka. (AFP)
AlJazeera