HARARE, Zimbabwe — Zimbabwe's ruling party said Friday there will be a presidential runoff election between President Robert Mugabe and opposition leader Morgan Tsvangirai.

ZANU-PF party secretary and Minister of State Didymus Mutasa also charged that the opposition bribed electoral officials and said his party would contest results of 16 parliamentary seats — enough to win back its majority.

Mutasa spoke at a news conference after a party politburo meeting, the first since elections results showed it has lost its control of parliament. The opposition claims to have won the presidency, but official returns in that race have not yet been released.

On Thursday, Zimbabwe's main opposition party Movement for Democratic Change said that Mugabe has "unleashed a war" in his bid to stay in power after party offices were raided and foreign journalists detained.

Mugabe has ruled Zimbabwe since his guerrilla army helped force an end to white minority rule and bring about an independent Zimbabwe in 1980, but his popularity has been battered by an economic freefall that followed the often-violent seizures of white-owned commercial farms in 2000.