Senegal's former prime minister is facing charges of taking part in a money laundering scheme with an unnamed African head of state.  The former prime minister denies the charges which his opposition party says are meant to silence political challengers ahead of March municipal elections.

Senegal's Interior Ministry says authorities intercepted mail exchanged with an unnamed African head of state indicating that the former prime minister was part of a scheme to launder money belonging to Gabon-based Senegalese businessman Abdoulaye Sall.

The businessman, who is a member of Macky Sall's still-unregistered opposition party, is already under arrest. In a statement announcing the charges, Interior Minister Cheikh Tidiane Sy says the investigation into their alleged illicit operation continues.

Speaking to supporters at his home early Tuesday morning, the former president of the National Assembly thanked them for their support during what he called "these moments of aggression."

Sall rejects accusations

Sall said the charges against him and members of his party are unfounded. Party spokesman  Seydou Gueye said it is a political attempt to silence Sall two months before local government elections. Gueye said the party will not be intimidated by what he called "the practices of another age" saying what he described as "the beleaguered regime" of President Abdoulaye Wade is guilty of "slander and authoritarianism."

Sall quit President Wade's ruling party three months ago when he was voted out as president of the National Assembly after the term of that office was reduced to one year. Sall had previously served as President Wade's energy minister and interior minister as well as government spokesman and director of the president's 2007 re-election campaign.

But the two men split after Sall called the president's son Karim before a hearing investigating his oversight of spending on last year's Organization of the Islamic Conference summit in Dakar. Karim Wade is currently standing as a candidate for mayor of the capital city in March elections.