Panaji, Mar 1 (IANS): The Congress in Goa Thursday launched a probe into the sound system failure during Prime Minister Manmohan Singh's election rally the day before.

State Congress president Subhash Shirodkar told reporters that the audio mixer used by the sound contractor had failed.

"We have launched an enquiry. The mixer used in the sound equipment had failed. The back up was also not working," Shirodkar said, refuting allegations of sabotage.

Manmohan Singh, who was addressing an election rally in Sanquelim, 40 km from here, had to face half an hour of embarrassment after the sound system failed. The prime minister was just two minutes into the speech when the glitch occurred.

The audio glitch resulted in chaos with Congress leaders scurrying around to get the sound system fixed, as Manmohan Singh sat watching the fracas.

Chief Minister Digambar Kamat, former chief ministers Francisco Sardinha and Pratapsing Rane, All India Congress Committee (AICC) functionaries B.K. Hariprasad and Sudhakar Reddy, parliamentarians Shantaram Naik and Sanjay Nirupam and several other dignitaries were present during the rally.

The Sanquelim rally was the last big political event by the Congress party before the March 3 assembly elections. The Congress is contesting 33 seats while its ally Nationalist Congress Party (NCP) is contesting seven.