Sudanese President Omar al-Bashir has been accused of siphoning off up to $9bn of his country's funds and placing it in foreign accounts, according to leaked US diplomatic cables.
Diplomats quoted the chief prosecutor of the International Criminal Court (ICC) as saying that much of the money may be stashed in London banks.
The allegations released by the Wikileaks website have been published by the Guardian newspaper.
Sudan has denied the claims.
The cables quoted ICC chief prosecutor Luis Moreno Ocampo as telling US officials that some of the funds may be held by the part-nationalised Lloyds Banking Group. He reportedly said it was time to go public with the scale of Mr Bashir's theft.
"Ocampo suggested if Bashir's stash of money were disclosed (he put the figure at $9bn), it would change Sudanese public opinion from him being a 'crusader' to that of a thief," one report by a senior US official said.
"Ocampo reported Lloyds bank in London may be holding or knowledgeable of the whereabouts of the money," the cable said.
Lloyds has responded by saying it has no evidence of holding funds in Mr Bashir's name.
"We have absolutely no evidence to suggest there is any connection between Lloyds Banking Group and Mr Bashir. The group's policy is to abide by the legal and regulatory obligations in all jurisdictions in which we operate," the bank said.
Correspondents say that if Mr Ocampo's claim about Bashir's fortune is correct, the Sudanese funds being held in London banks amount to one tenth of the country's annual GDP.
Claims 'ludicrous'Mr Ocampo is said to have discussed evidence of the stash with the Americans just days after issuing an arrest warrant for Mr Bashir in March 2009 - the first issued by the court against a serving head of state.
Mr Bashir was indicted last year for seven counts of war crimes and crimes against humanity in the Darfur region, with a further three counts of genocide added in July.
A spokesperson for the Sudanese government dismissed the claim, describing it as further evidence of the ICC's political agenda in discrediting the Sudanese government.
"To claim that the president can control the treasury and take money to put into his own accounts is ludicrous - it is a laughable claim by the ICC prosecutor," Khalid al-Mubarak, government spokesperson at the Sudanese embassy in London, told the Guardian.
"Ocampo is a maverick, and this is just part of his political agenda. He has failed miserably in all his cases and has refused to investigate Iraq or Gaza - he needs success and he has targeted Bashir to increase his own importance".
"Attempts to smear not only Bashir but Sudan as a whole are well known, and are clearly linked with anti-Arab sentiments and Islamophobia," Mr Mubarak said. BBC News
