Israeli fraud squad detectives have interviewed Prime Minister Mr Ariel Sharon over allegations of illegal campaign donations during primaries for the leadership of his Likud party.
The police refused to comment on what they said was an ongoing investigation. An aide to Mr Sharon would neither confirm nor deny that such an interview took place.
Mr Sharon denies any involvement in fundraising for his campaign. Among those already questioned over the allegations were his son, Omri, and Mr Uri Shani. On Friday Mr Shani unexpectedly resigned as director of the Prime Minister's Office.
The Israeli attorney-general, Mr Elyakim Rubinstein, ordered the investigation after the country's state comptroller published a scathing report listing violations of Israel's campaign laws, which strictly limit fundraising from abroad.
The report said Nr Omri Sharon, in charge of campaign financing, raised large sums of money outside Israel through a dummy company as a front.
The Justice Ministry has said it expects a lengthy investigation before Mr Rubinstein decides whether to file indictments against Mr Sharon or his son.
After the comptroller's report was released last September, Mr Sharon issued a statement saying he had "complete faith in the justice system and the state comptroller." It said: "Any violations were without a doubt unintentional, and will be corrected in full".
AP