Police in Senegal have fired tear gas to disperse supporters of a former prime minister, as he was being questioned over public spending.
Idrissa Seck is seen as one of the front-runners to succeed President Wade
Idrissa Seck was instrumental in Abdoulaye Wade's 2000 presidential election victory but the two have since fallen out.
On Wednesday, Mr Wade accused Mr Seck of spending double the amount agreed on a road to his home town, Thies.
Mr Seck denies wrong-doing and his supporters say he is being victimised.
Hundreds of his supporters gathered outside his house in Dakar on Thursday night and went with him to the police station on Friday morning.
He is being questioned after Mr Wade said in a national television address that Mr Seck had spent $85m on renovating a road between the capital, Dakar, and Thies, when cabinet had only agreed $45m.
Mr Seck has said he can account for all of the money.
After 15 months as prime minister, he was fired last year, amidst deep divisions in the ruling Senegalese Democratic Party (PDS).
Earlier this year, his house in Dakar was pelted with rotten eggs, animal blood and excrement.
He has said that he remains a PDS member but that he might run against the party in next year's parliamentary elections.
Presidential elections are due in 2007 and Mr Seck is seen as one of the front-runners, although he has said he would not stand against Mr Wade, 77.