The Supreme Court has threatened to jail Naveed Ahsan if he does not act
Pakistan's Supreme Court has threatened to jail the head of the country's anti-corruption agency unless he reopens hundreds of corruption cases.
The court said the chairman of the National Accountability Bureau, Naveed Ahsan, would be in contempt of court if he did not act within 24 hours.
Mr Ahsan is due to appear before the court on Wednesday.
A 2007 amnesty invalidated charges against top politicians and officials, but the court threw it out in December.
It has been demanding the revival of corruption cases ever since.
Several of the pending cases involve President Asif Zardari.
Before taking office, he spent years in jail after being convicted on corruption charges he says were politically motivated.
The court's decision to declare the amnesty illegal opens the way to possible prosecution for Mr Zardari's political allies, although he is still protected by presidential immunity.
The amnesty, which protected officials and politicians from charges dating back to the 1990s, was introduced by former military leader Gen Pervez Musharraf.
It was seen as the basis for a power-sharing deal between Mr Musharraf and Mr Zardari's wife, former Prime Minister Benazir Bhutto, who was assassinated in December 2007.
It emerged only in late 2009 that more than 8,000 politicians and officials had benefited from the legislation.
Meanwhile, the director general of Pakistan's top police investigation agency, Ahmed Riaz Sheikh, has reportedly been detained on orders of the Supreme Court.
His lawyer, Rashid Rizvi, told Reuters news agency he had been sent into police custody after he "withdrew his challenge to his conviction".