The Supreme court in Bangladesh has overturned a ruling made by a lower court to free former Prime Minister Khaleda Zia on bail.
Khaleda Zia is also facing charges of tax evasion
The court upheld an appeal by the army-backed interim government.
The decision means that Ms Zia must remain in detention on extortion and corruption charges which she rejects.
Ms Zia's bitter political rival - former Prime Minister Sheikh Hasina of the Awami League - is also being held on charges 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 around 150 politicians in what it says is a crackdown on corruption.
Prosecuting lawyers insist that that following Thursday's Supreme Court order, the trial of Khaleda Zia will go ahead.
She and her son Arafat Rahman were arrested early last month over allegations of fraud in relation to the award of a cargo-handling contract in 2003.
The High Court over the weekend ordered her to be freed on bail and the charges against her to be dropped.
It ruled that the charges were not lawful because she could not be tried under special emergency laws for an offence committed before the imposition of emergency in January this year.
But the army-backed caretaker government, which has vowed to rid the country of corruption before elections next year, filed an appeal on Tuesday against the order.