The late Nigerian dictator Sani Abacha and his family stole $4.3bn from public funds during his four and a half years in power, the Nigerian Government says.

The announcement by President Olesegun Obasanjo is the first time he has put a figure on the fortune illegally transferred from public accounts by Nigeria's previous rulers.

President Obasanjo said the Abacha family had

• directly siphoned $2.3bn from the national treasury
• awarded contracts worth a further $1bn to front companies
• extorted another $1bn from third party foreign contractors

Mr Obasanjo said his government was determined to recover as much of the money as possible.

He said most of the money had been illegally transferred abroad.

The Swiss authorities have frozen $645m in bank accounts belonging General Abacha and his associates while they conduct an investigation.

But the Nigerian has reported that the government is also investigating the transfer of money to banks in the United Kingdom, France, Lebanon and the United States.

Sani Abacha seized power in Nigeria in November 1993 and ruled until his sudden death in June 1998.

His death paved the way for the reinstatement of civilian government in Nigeria.