Around 40 per cent polling was registered in 12 constituencies of Bastar and one in Rajnandgaon district till 1 pm, electoral officers said.
Ahead of polling in Naxal-hit Bastar district, a clash broke out between supporters of BJP and Congress following which cases were registered against members of both the groups.
A police personnel was injured when a pressure bomb laid by Naxals exploded in Kanker district of north Bastar. The incident took place when the jawan was removing the bomb, placed beneath the earth, for defusing near Parlakot village, Kanker Additional Superintendent of Police CD Tandon told PTI.
As the polling got underway, explosives were recovered from separate places in Bastar region. According to a senior police official, a pipe bomb of 10 kg was recovered from Murkinar area of Bijapur district while 8 bombs were found in Mangnar area and two in Kuwakonda area of Dantewada district were recovered by security forces during de-mining operations.
Besides, tiffin bombs in Orcha area of Narayanpur district and a bomb in Kanker district were also recovered.
Voting failed to kick start in two hyper sensitive polling booths - Durgapur and Sitaram - of Kanker as polling parties were unable to reach the venue owing to Naxal resistance and looting of EVM machines from polling parties.
Encounters between security forces and Maoists were also reported near few polling booths in Naxal-hit Dantewada district and Bijapur of southern Chhattisgarh.
A total of 143 candidates from 12 constituencies are in the fray in Bastar division and six constituencies of Rajnandgaon district with an electorate of 29,33,200 in the first of the two-phase polls to the 90-member Assembly in the state where Chief Minister Raman Singh is hoping for a hat-trick.