JAKARTA, July 26: Retired military general Susilo Bambang Yudhoyono topped the first round of Indonesia's presidential elections, but failed to poll more than 50 per cent - setting the stage for a runoff on Sept 20 , the General Elections Commission (KPU) announced.

The tally on Monday was marred by a minor explosion at election commission headquarters. Mr Yudhoyono won 33.57 per cent of the 118.6 million valid votes cast in the presidential polls held on July 5, with incumbent President Megawati Sukarnoputri placing second with 26.6 per cent.

"According to existing regulations for presidential elections this mean Mr Yudhoyono and Ms Megawati will contest the second round," said KPU Secretary-General Hsa Yusacc. The final tally was delayed several hours by the small explosion in the KPU's ladies toilet, possibly a bomb. There were no injuries but the premises were evacuated. -dpa