Niger's opposition parties say they will not recognize results from presidential and legislative elections that took place Sunday, citing fraud.

The candidates from opposition parties said in a statement Tuesday they would not recognize a victory by incumbent President Issoufou Mahamadou. They accused the government of voter intimidation and warned of false results. Fifteen candidates are vying for the presidency.

The electoral commission has released partial results from about 30 percent of polling stations that give Mahamadou a lead. Provisional results are expected by Friday.

The heads of observation missions, including the African Union, said late Monday that Niger's Feb. 21 elections took place "in a calm and serene environment."

Niger has about 7.5 million voters registered for the election and candidates are also competing for 171 legislative seats.