Curfew has been clamped for five days from Wednesday afternoon.

Police said the trouble erupted after the farmers protesting a steep fall in groundnut prices went berserk, setting ablaze two police jeeps, three Karnataka State Road Transport Corporation buses and damaging about 25 lorries on the busy Pune-Bangalore National Highway.

While Sira Town Police Inspector Sai Prakash was stabbed to death by agitating farmers, 15 farmers were injured when police resorted to lathi-charge, tear gas shell burst and firing. Over 42 police personnel were injured when the farmers attacked them, it is learnt.

The violence began around 8.30 am, when over 2,000 farmers, who were agitating near the Agricultural Products Marketing CommitteeYard since Tuesday evening turned violent. The farmers alleged that the APMC officials had colluded with local oil mill owners and caused the price crash.

Sai Prakash, who tried to prevent the mob from setting a bus ablaze (which is said to be carrying 50 passengers), was stabbed to death. The police opened fire killing five farmers. Karnataka Labour Minister Satyanarayana, who is incharge of the district, is understood to have warned the district administration about the possibility of such an incident following the crash in groundnut prices. The resignation was owning to the failure of the state in tackling the issue inspite of prior knowledge of the situation.