A plea bargain in a US court has revealed details of an alleged Libyan plot to assassinate Saudi Arabia's de facto leader Crown Prince Abdullah.
Saudi Arabia's Crown Prince Abdullah was the alleged target
Leading US Muslim activist Abdurahman Alamoudi admitted taking part in the plot, as he pleaded guilty to three charges of illegal dealings with Libya.
US Attorney General John Ashcroft said the case has provided "critical intelligence" in the war on terror.
Libya has denied plotting to assassinate the Crown Prince.
The US Justice Department described an elaborate plot, in which Mr Alamoudi - a founder of the American Muslim Council and the American Muslim Foundation - served as a go-between between top Libyan officials and Saudi dissidents.
A department statement says Libyan leader Muammar Gaddafi was upset after clashing with the Crown Prince during an Arab League summit in March 2003.
The Saudi walked out questioning how Col Gaddafi came to power, after the Libyan leader criticised Saudi Arabia for hosting US troops ahead of the Iraq war.
Mr Alamoudi said he was summoned to Tripoli and asked by unidentified Libyan officials to introduce them to Saudi dissidents who could cause "headaches" for Riyadh.
"As the scheme continued, however, Alamoudi learned that the actual objective of the scheme was the assassination of Saudi Crown Prince Abdullah," the statement said.
The 52-year-old naturalised US citizen - who was born in Eritrea - was not charged in relation to the assassination plot.
Instead, he pleaded guilty to three criminal charges, including tax and immigration violations.
Mr Alamoudi is said to have made contact with at least two Saudis in Britain and brought them hundreds of thousands of dollars in cash.
In August 2003, he was caught at London's Heathrow airport carrying $340,000, according to the Justice Department statement.
It says that although the money was seized, Mr Alamoudi was allowed to continue his travels, including stops in Syria, Libya and Egypt.
The department says the defendant illegally received other funds from the Libyan government.
The alleged plan to kill the Saudi Crown Prince is worrying US officials, at a time when the US and Libya are mending relations.
Tripoli's ties with the West have blossomed since it renounced weapons of mass destruction in December.
"These reports are of concern," deputy US State Department spokesman Adam Ereli said of the information
contained in the Alamoudi case.
"We're examining them. And it's also clear... that our relationship with Libya cannot be fully normal until it's absolutely clear that Libya's no longer participating in any kind of terrorist activity," he added.
Mr Ashcroft, for his part, said the conviction was a "milestone" in the war on terror, and called Mr Alamoudi "a major player in the financial support of terrorism".
He faces a maximum sentence of 23 years in prison when he is sentenced on 15 October, and is likely to be stripped of his US citizenship.
Mr Alamouri's lawyer said the government had conceded that his client's role in the alleged assassination plot was minimal.